Add the HandleConfigure module

This module handles the configure.ac files on the Automake side.  It required
to modify a bit the scan_autoconf_[file|traces] functions so we can pass them
the environment var for autoconf as arguments from the main file (otherwise it
wouldn't work).

* lib/Automake/HandleConfigure.pm: Module for handling configure.ac for automake.
* lib/Automake/Utils.pm: Add some necessary functions for the new
  HandleConfigure module.

5 files changed, 1002 insertions, 954 deletions

diff --git a/bin/automake.in b/bin/automake.in
index 301c850e4..5a59c349b 100755
--- a/bin/automake.in
+++ b/bin/automake.in
@@ -62,6 +62,7 @@ use Automake::File;
 use Automake::FileUtils;
 use Automake::General;
 use Automake::Global;
+use Automake::HandleConfigure;
 use Automake::LangHandling;
 use Automake::Language;
 use Automake::Location;
@@ -90,7 +91,6 @@ sub am_primary_prefixes;
 sub append_exeext (&$);
 sub check_canonical_spelling;
 sub check_directories_in_var;
-sub check_directory;
 sub check_libobjs_sources;
 sub check_trailing_slash ($\$);
 sub check_typos ();
@@ -142,19 +142,10 @@ sub handle_user_recursion ();
 sub initialize_per_input ();
 sub is_valid_test_extension;
 sub parse_arguments ();
-sub prepend_srcdir;
 sub print_autodist_files;
 sub read_am_file;
 sub read_main_am_file;
-sub rewrite_inputs_into_dependencies;
-sub scan_aclocal_m4 ();
-sub scan_autoconf_config_files;
-sub scan_autoconf_files ();
-sub scan_autoconf_traces;
 sub shadow_unconditionally;
-sub split_config_file_spec;
-sub substitute_ac_subst_variables;
-sub substitute_ac_subst_variables_worker;
 sub target_cmp;
 sub usage ();
 sub user_phony_rule;
@@ -2726,45 +2717,6 @@ sub handle_dist ()
 }
 
 
-# check_directory ($NAME, $WHERE [, $RELATIVE_DIR = "."])
-# -------------------------------------------------------
-# Ensure $NAME is a directory (in $RELATIVE_DIR), and that it uses a sane
-# name.  Use $WHERE as a location in the diagnostic, if any.
-sub check_directory
-{
-  my ($dir, $where, $reldir) = @_;
-  $reldir = '.' unless defined $reldir;
-
-  error $where, "required directory $reldir/$dir does not exist"
-    unless -d "$reldir/$dir";
-
-  # If an 'obj/' directory exists, BSD make will enter it before
-  # reading 'Makefile'.  Hence the 'Makefile' in the current directory
-  # will not be read.
-  #
-  #  % cat Makefile
-  #  all:
-  #          echo Hello
-  #  % cat obj/Makefile
-  #  all:
-  #          echo World
-  #  % make      # GNU make
-  #  echo Hello
-  #  Hello
-  #  % pmake     # BSD make
-  #  echo World
-  #  World
-  msg ('portability', $where,
-       "naming a subdirectory 'obj' causes troubles with BSD make")
-    if $dir eq 'obj';
-
-  # 'aux' is probably the most important of the following forbidden name,
-  # since it's tempting to use it as an AC_CONFIG_AUX_DIR.
-  msg ('portability', $where,
-       "name '$dir' is reserved on W32 and DOS platforms")
-    if grep (/^\Q$dir\E$/i, qw/aux lpt1 lpt2 lpt3 com1 com2 com3 com4 con prn/);
-}
-
 # check_directories_in_var ($VARIABLE)
 # ------------------------------------
 # Recursively check all items in variables $VARIABLE as directories
@@ -2800,451 +2752,6 @@ sub handle_subdirs ()
 }
 
 
-# ($REGEN, @DEPENDENCIES)
-# scan_aclocal_m4
-# ---------------
-# If aclocal.m4 creation is automated, return the list of its dependencies.
-sub scan_aclocal_m4 ()
-{
-  my $regen_aclocal = 0;
-
-  set_seen 'CONFIG_STATUS_DEPENDENCIES';
-  set_seen 'CONFIGURE_DEPENDENCIES';
-
-  if (-f 'aclocal.m4')
-    {
-      define_variable ("ACLOCAL_M4", '$(top_srcdir)/aclocal.m4', INTERNAL);
-
-      my $aclocal = new Automake::XFile "< aclocal.m4";
-      my $line = $aclocal->getline;
-      $regen_aclocal = $line =~ 'generated automatically by aclocal';
-    }
-
-  my @ac_deps = ();
-
-  if (set_seen ('ACLOCAL_M4_SOURCES'))
-    {
-      push (@ac_deps, '$(ACLOCAL_M4_SOURCES)');
-      msg_var ('obsolete', 'ACLOCAL_M4_SOURCES',
-	       "'ACLOCAL_M4_SOURCES' is obsolete.\n"
-	       . "It should be safe to simply remove it");
-    }
-
-  # Note that it might be possible that aclocal.m4 doesn't exist but
-  # should be auto-generated.  This case probably isn't very
-  # important.
-
-  return ($regen_aclocal, @ac_deps);
-}
-
-
-# Helper function for 'substitute_ac_subst_variables'.
-sub substitute_ac_subst_variables_worker
-{
-  my ($token) = @_;
-  return "\@$token\@" if var $token;
-  return "\${$token\}";
-}
-
-# substitute_ac_subst_variables ($TEXT)
-# -------------------------------------
-# Replace any occurrence of ${FOO} in $TEXT by @FOO@ if FOO is an AC_SUBST
-# variable.
-sub substitute_ac_subst_variables
-{
-  my ($text) = @_;
-  $text =~ s/\$[{]([^ \t=:+{}]+)}/substitute_ac_subst_variables_worker ($1)/ge;
-  return $text;
-}
-
-# @DEPENDENCIES
-# prepend_srcdir (@INPUTS)
-# ------------------------
-# Prepend $(srcdir) or $(top_srcdir) to all @INPUTS.  The idea is that
-# if an input file has a directory part the same as the current
-# directory, then the directory part is simply replaced by $(srcdir).
-# But if the directory part is different, then $(top_srcdir) is
-# prepended.
-sub prepend_srcdir
-{
-  my (@inputs) = @_;
-  my @newinputs;
-
-  foreach my $single (@inputs)
-    {
-      if (dirname ($single) eq $relative_dir)
-	{
-	  push (@newinputs, '$(srcdir)/' . basename ($single));
-	}
-      else
-	{
-	  push (@newinputs, '$(top_srcdir)/' . $single);
-	}
-    }
-  return @newinputs;
-}
-
-# @DEPENDENCIES
-# rewrite_inputs_into_dependencies ($OUTPUT, @INPUTS)
-# ---------------------------------------------------
-# Compute a list of dependencies appropriate for the rebuild
-# rule of
-#   AC_CONFIG_FILES($OUTPUT:$INPUT[0]:$INPUTS[1]:...)
-# Also distribute $INPUTs which are not built by another AC_CONFIG_FOOs.
-sub rewrite_inputs_into_dependencies
-{
-  my ($file, @inputs) = @_;
-  my @res = ();
-
-  for my $i (@inputs)
-    {
-      # We cannot create dependencies on shell variables.
-      next if (substitute_ac_subst_variables $i) =~ /\$/;
-
-      if (exists $ac_config_files_location{$i} && $i ne $file)
-	{
-	  my $di = dirname $i;
-	  if ($di eq $relative_dir)
-	    {
-	      $i = basename $i;
-	    }
-	  # In the top-level Makefile we do not use $(top_builddir), because
-	  # we are already there, and since the targets are built without
-	  # a $(top_builddir), it helps BSD Make to match them with
-	  # dependencies.
-	  elsif ($relative_dir ne '.')
-	    {
-	      $i = '$(top_builddir)/' . $i;
-	    }
-	}
-      else
-	{
-	  msg ('error', $ac_config_files_location{$file},
-	       "required file '$i' not found")
-	    unless $i =~ /\$/ || exists $output_files{$i} || -f $i;
-	  ($i) = prepend_srcdir ($i);
-	  push_dist_common ($i);
-	}
-      push @res, $i;
-    }
-  return @res;
-}
-
-
-
-# handle_configure ($MAKEFILE_AM, $MAKEFILE_IN, $MAKEFILE, @INPUTS)
-# -----------------------------------------------------------------
-# Handle remaking and configure stuff.
-# We need the name of the input file, to do proper remaking rules.
-sub handle_configure
-{
-  my ($makefile_am, $makefile_in, $makefile, @inputs) = @_;
-
-  prog_error 'empty @inputs'
-    unless @inputs;
-
-  my ($rel_makefile_am, $rel_makefile_in) = prepend_srcdir ($makefile_am,
-							    $makefile_in);
-  my $rel_makefile = basename $makefile;
-
-  my $colon_infile = ':' . join (':', @inputs);
-  $colon_infile = '' if $colon_infile eq ":$makefile.in";
-  my @rewritten = rewrite_inputs_into_dependencies ($makefile, @inputs);
-  my ($regen_aclocal_m4, @aclocal_m4_deps) = scan_aclocal_m4;
-  define_pretty_variable ('am__aclocal_m4_deps', TRUE, INTERNAL,
-			  @configure_deps, @aclocal_m4_deps,
-			  '$(top_srcdir)/' . $configure_ac);
-  my @configuredeps = ('$(am__aclocal_m4_deps)', '$(CONFIGURE_DEPENDENCIES)');
-  push @configuredeps, '$(ACLOCAL_M4)' if -f 'aclocal.m4';
-  define_pretty_variable ('am__configure_deps', TRUE, INTERNAL,
-			  @configuredeps);
-
-  my $automake_options = '--' . $strictness_name .
-			 (global_option 'no-dependencies' ? ' --ignore-deps' : '');
-
-  $output_rules .= file_contents
-    ('configure',
-     new Automake::Location,
-     MAKEFILE              => $rel_makefile,
-     'MAKEFILE-DEPS'       => "@rewritten",
-     'CONFIG-MAKEFILE'     => ($relative_dir eq '.') ? '$@' : '$(subdir)/$@',
-     'MAKEFILE-IN'         => $rel_makefile_in,
-     'HAVE-MAKEFILE-IN-DEPS' => (@include_stack > 0),
-     'MAKEFILE-IN-DEPS'    => "@include_stack",
-     'MAKEFILE-AM'         => $rel_makefile_am,
-     'AUTOMAKE-OPTIONS'    => $automake_options,
-     'MAKEFILE-AM-SOURCES' => "$makefile$colon_infile",
-     'REGEN-ACLOCAL-M4'    => $regen_aclocal_m4,
-     VERBOSE               => verbose_flag ('GEN'));
-
-  if ($relative_dir eq '.')
-    {
-      push_dist_common ('acconfig.h')
-	if -f 'acconfig.h';
-    }
-
-  # If we have a configure header, require it.
-  my $hdr_index = 0;
-  my @distclean_config;
-  foreach my $spec (@config_headers)
-    {
-      $hdr_index += 1;
-      # $CONFIG_H_PATH: config.h from top level.
-      my ($config_h_path, @ins) = split_config_file_spec ($spec);
-      my $config_h_dir = dirname ($config_h_path);
-
-      # If the header is in the current directory we want to build
-      # the header here.  Otherwise, if we're at the topmost
-      # directory and the header's directory doesn't have a
-      # Makefile, then we also want to build the header.
-      if ($relative_dir eq $config_h_dir
-	  || ($relative_dir eq '.' && ! is_make_dir ($config_h_dir)))
-	{
-	  my ($cn_sans_dir, $stamp_dir);
-	  if ($relative_dir eq $config_h_dir)
-	    {
-	      $cn_sans_dir = basename ($config_h_path);
-	      $stamp_dir = '';
-	    }
-	  else
-	    {
-	      $cn_sans_dir = $config_h_path;
-	      if ($config_h_dir eq '.')
-		{
-		  $stamp_dir = '';
-		}
-	      else
-		{
-		  $stamp_dir = $config_h_dir . '/';
-		}
-	    }
-
-	  # This will also distribute all inputs.
-	  @ins = rewrite_inputs_into_dependencies ($config_h_path, @ins);
-
-	  # Cannot define rebuild rules for filenames with shell variables.
-	  next if (substitute_ac_subst_variables $config_h_path) =~ /\$/;
-
-	  # Header defined in this directory.
-	  my @files;
-	  if (-f $config_h_path . '.top')
-	    {
-	      push (@files, "$cn_sans_dir.top");
-	    }
-	  if (-f $config_h_path . '.bot')
-	    {
-	      push (@files, "$cn_sans_dir.bot");
-	    }
-
-	  push_dist_common (@files);
-
-	  # For now, acconfig.h can only appear in the top srcdir.
-	  if (-f 'acconfig.h')
-	    {
-	      push (@files, '$(top_srcdir)/acconfig.h');
-	    }
-
-	  my $stamp = "${stamp_dir}stamp-h${hdr_index}";
-	  $output_rules .=
-	    file_contents ('remake-hdr',
-			   new Automake::Location,
-			   FILES            => "@files",
-			   'FIRST-HDR'      => ($hdr_index == 1),
-			   CONFIG_H         => $cn_sans_dir,
-			   CONFIG_HIN       => $ins[0],
-			   CONFIG_H_DEPS    => "@ins",
-			   CONFIG_H_PATH    => $config_h_path,
-			   STAMP            => "$stamp");
-
-	  push @distclean_config, $cn_sans_dir, $stamp;
-	}
-    }
-
-  $output_rules .= file_contents ('clean-hdr',
-				  new Automake::Location,
-				  FILES => "@distclean_config")
-    if @distclean_config;
-
-  # Distribute and define mkinstalldirs only if it is already present
-  # in the package, for backward compatibility (some people may still
-  # use $(mkinstalldirs)).
-  # TODO: start warning about this in Automake 1.14, and have
-  # TODO: Automake 2.0 drop it (and the mkinstalldirs script
-  # TODO: as well).
-  my $mkidpath = "$config_aux_dir/mkinstalldirs";
-  if (-f $mkidpath)
-    {
-      # Use require_file so that any existing script gets updated
-      # by --force-missing.
-      require_conf_file ($mkidpath, FOREIGN, 'mkinstalldirs');
-      define_variable ('mkinstalldirs',
-		       "\$(SHELL) $am_config_aux_dir/mkinstalldirs", INTERNAL);
-    }
-  else
-    {
-      # Use $(install_sh), not $(MKDIR_P) because the latter requires
-      # at least one argument, and $(mkinstalldirs) used to work
-      # even without arguments (e.g. $(mkinstalldirs) $(conditional_dir)).
-      define_variable ('mkinstalldirs', '$(install_sh) -d', INTERNAL);
-    }
-
-  reject_var ('CONFIG_HEADER',
-	      "'CONFIG_HEADER' is an anachronism; now determined "
-	      . "automatically\nfrom '$configure_ac'");
-
-  my @config_h;
-  foreach my $spec (@config_headers)
-    {
-      my ($out, @ins) = split_config_file_spec ($spec);
-      # Generate CONFIG_HEADER define.
-      if ($relative_dir eq dirname ($out))
-	{
-	  push @config_h, basename ($out);
-	}
-      else
-	{
-	  push @config_h, "\$(top_builddir)/$out";
-	}
-    }
-  define_variable ("CONFIG_HEADER", "@config_h", INTERNAL)
-    if @config_h;
-
-  # Now look for other files in this directory which must be remade
-  # by config.status, and generate rules for them.
-  my @actual_other_files = ();
-  # These get cleaned only in a VPATH build.
-  my @actual_other_vpath_files = ();
-  foreach my $lfile (@other_input_files)
-    {
-      my $file;
-      my @inputs;
-      if ($lfile =~ /^([^:]*):(.*)$/)
-	{
-	  # This is the ":" syntax of AC_OUTPUT.
-	  $file = $1;
-	  @inputs = split (':', $2);
-	}
-      else
-	{
-	  # Normal usage.
-	  $file = $lfile;
-	  @inputs = $file . '.in';
-	}
-
-      # Automake files should not be stored in here, but in %MAKE_LIST.
-      prog_error ("$lfile in \@other_input_files\n"
-		  . "\@other_input_files = (@other_input_files)")
-	if -f $file . '.am';
-
-      my $local = basename ($file);
-
-      # We skip files that aren't in this directory.  However, if
-      # the file's directory does not have a Makefile, and we are
-      # currently doing '.', then we create a rule to rebuild the
-      # file in the subdir.
-      my $fd = dirname ($file);
-      if ($fd ne $relative_dir)
-	{
-	  if ($relative_dir eq '.' && ! is_make_dir ($fd))
-	    {
-	      $local = $file;
-	    }
-	  else
-	    {
-	      next;
-	    }
-	}
-
-      my @rewritten_inputs = rewrite_inputs_into_dependencies ($file, @inputs);
-
-      # Cannot output rules for shell variables.
-      next if (substitute_ac_subst_variables $local) =~ /\$/;
-
-      my $condstr = '';
-      my $cond = $ac_config_files_condition{$lfile};
-      if (defined $cond)
-        {
-	  $condstr = $cond->subst_string;
-	  Automake::Rule::define ($local, $configure_ac, RULE_AUTOMAKE, $cond,
-				  $ac_config_files_location{$file});
-        }
-      $output_rules .= ($condstr . $local . ': '
-			. '$(top_builddir)/config.status '
-			. "@rewritten_inputs\n"
-			. $condstr . "\t"
-			. 'cd $(top_builddir) && '
-			. '$(SHELL) ./config.status '
-			. ($relative_dir eq '.' ? '' : '$(subdir)/')
-			. '$@'
-			. "\n");
-      push (@actual_other_files, $local);
-    }
-
-  # For links we should clean destinations and distribute sources.
-  foreach my $spec (@config_links)
-    {
-      my ($link, $file) = split /:/, $spec;
-      # Some people do AC_CONFIG_LINKS($computed).  We only handle
-      # the DEST:SRC form.
-      next unless $file;
-      my $where = $ac_config_files_location{$link};
-
-      # Skip destinations that contain shell variables.
-      if ((substitute_ac_subst_variables $link) !~ /\$/)
-	{
-	  # We skip links that aren't in this directory.  However, if
-	  # the link's directory does not have a Makefile, and we are
-	  # currently doing '.', then we add the link to CONFIG_CLEAN_FILES
-	  # in '.'s Makefile.in.
-	  my $local = basename ($link);
-	  my $fd = dirname ($link);
-	  if ($fd ne $relative_dir)
-	    {
-	      if ($relative_dir eq '.' && ! is_make_dir ($fd))
-		{
-		  $local = $link;
-		}
-	      else
-		{
-		  $local = undef;
-		}
-	    }
-	  if ($file ne $link)
-	    {
-	      push @actual_other_files, $local if $local;
-	    }
-	  else
-	    {
-	      push @actual_other_vpath_files, $local if $local;
-	    }
-	}
-
-      # Do not process sources that contain shell variables.
-      if ((substitute_ac_subst_variables $file) !~ /\$/)
-	{
-	  my $fd = dirname ($file);
-
-	  # We distribute files that are in this directory.
-	  # At the top-level ('.') we also distribute files whose
-	  # directory does not have a Makefile.
-	  if (($fd eq $relative_dir)
-	      || ($relative_dir eq '.' && ! is_make_dir ($fd)))
-	    {
-	      # The following will distribute $file as a side-effect when
-	      # it is appropriate (i.e., when $file is not already an output).
-	      # We do not need the result, just the side-effect.
-	      rewrite_inputs_into_dependencies ($link, $file);
-	    }
-	}
-    }
-
-  # These files get removed by "make distclean".
-  define_pretty_variable ('CONFIG_CLEAN_FILES', TRUE, INTERNAL,
-			  @actual_other_files);
-  define_pretty_variable ('CONFIG_CLEAN_VPATH_FILES', TRUE, INTERNAL,
-			  @actual_other_vpath_files);
-}
-
 sub handle_headers ()
 {
     my @r = am_install_var ('-defaultdist', 'header', 'HEADERS', 'include',
@@ -3950,454 +3457,6 @@ sub handle_minor_options ()
 
 ################################################################
 
-# ($OUTPUT, @INPUTS)
-# split_config_file_spec ($SPEC)
-# ------------------------------
-# Decode the Autoconf syntax for config files (files, headers, links
-# etc.).
-sub split_config_file_spec
-{
-  my ($spec) = @_;
-  my ($output, @inputs) = split (/:/, $spec);
-
-  push @inputs, "$output.in"
-    unless @inputs;
-
-  return ($output, @inputs);
-}
-
-my %make_list;
-
-# scan_autoconf_config_files ($WHERE, $CONFIG-FILES)
-# --------------------------------------------------
-# Study $CONFIG-FILES which is the first argument to AC_CONFIG_FILES
-# (or AC_OUTPUT).
-sub scan_autoconf_config_files
-{
-  my ($where, $config_files) = @_;
-
-  # Look at potential Makefile.am's.
-  foreach (split ' ', $config_files)
-    {
-      # Must skip empty string for Perl 4.
-      next if $_ eq "\\" || $_ eq '';
-
-      # Handle $local:$input syntax.
-      my ($local, @rest) = split (/:/);
-      @rest = ("$local.in",) unless @rest;
-      # Keep in sync with test 'conffile-leading-dot.sh'.
-      msg ('unsupported', $where,
-           "omit leading './' from config file names such as '$local';"
-           . "\nremake rules might be subtly broken otherwise")
-        if ($local =~ /^\.\//);
-      my $input = locate_am @rest;
-      if ($input)
-	{
-	  # We have a file that automake should generate.
-	  $make_list{$input} = join (':', ($local, @rest));
-	}
-      else
-	{
-	  # We have a file that automake should cause to be
-	  # rebuilt, but shouldn't generate itself.
-	  push (@other_input_files, $_);
-	}
-      $ac_config_files_location{$local} = $where;
-      $ac_config_files_condition{$local} =
-        new Automake::Condition (@cond_stack)
-          if (@cond_stack);
-    }
-}
-
-
-sub scan_autoconf_traces
-{
-  my ($filename) = @_;
-
-  # Macros to trace, with their minimal number of arguments.
-  #
-  # IMPORTANT: If you add a macro here, you should also add this macro
-  # =========  to Automake-preselection in autoconf/lib/autom4te.in.
-  my %traced = (
-		AC_CANONICAL_BUILD => 0,
-		AC_CANONICAL_HOST => 0,
-		AC_CANONICAL_TARGET => 0,
-		AC_CONFIG_AUX_DIR => 1,
-		AC_CONFIG_FILES => 1,
-		AC_CONFIG_HEADERS => 1,
-		AC_CONFIG_LIBOBJ_DIR => 1,
-		AC_CONFIG_LINKS => 1,
-		AC_FC_SRCEXT => 1,
-		AC_INIT => 0,
-		AC_LIBSOURCE => 1,
-		AC_REQUIRE_AUX_FILE => 1,
-		AC_SUBST_TRACE => 1,
-		AM_AUTOMAKE_VERSION => 1,
-                AM_PROG_MKDIR_P => 0,
-		AM_CONDITIONAL => 2,
-		AM_EXTRA_RECURSIVE_TARGETS => 1,
-		AM_GNU_GETTEXT => 0,
-		AM_GNU_GETTEXT_INTL_SUBDIR => 0,
-		AM_INIT_AUTOMAKE => 0,
-		AM_MAINTAINER_MODE => 0,
-		AM_PROG_AR => 0,
-		_AM_SUBST_NOTMAKE => 1,
-		_AM_COND_IF => 1,
-		_AM_COND_ELSE => 1,
-		_AM_COND_ENDIF => 1,
-		LT_SUPPORTED_TAG => 1,
-		_LT_AC_TAGCONFIG => 0,
-		m4_include => 1,
-		m4_sinclude => 1,
-		sinclude => 1,
-	      );
-
-  my $traces = ($ENV{AUTOCONF} || '@am_AUTOCONF@') . " ";
-
-  # Use a separator unlikely to be used, not ':', the default, which
-  # has a precise meaning for AC_CONFIG_FILES and so on.
-  $traces .= join (' ',
-		   map { "--trace=$_" . ':\$f:\$l::\$d::\$n::\${::}%' }
-		   (keys %traced));
-
-  my $tracefh = new Automake::XFile ("$traces $filename |");
-  verb "reading $traces";
-
-  @cond_stack = ();
-  my $where;
-
-  while ($_ = $tracefh->getline)
-    {
-      chomp;
-      my ($here, $depth, @args) = split (/::/);
-      $where = new Automake::Location $here;
-      my $macro = $args[0];
-
-      prog_error ("unrequested trace '$macro'")
-	unless exists $traced{$macro};
-
-      # Skip and diagnose malformed calls.
-      if ($#args < $traced{$macro})
-	{
-	  msg ('syntax', $where, "not enough arguments for $macro");
-	  next;
-	}
-
-      # Alphabetical ordering please.
-      if ($macro eq 'AC_CANONICAL_BUILD')
-	{
-	  if ($seen_canonical <= AC_CANONICAL_BUILD)
-	    {
-	      $seen_canonical = AC_CANONICAL_BUILD;
-	    }
-	}
-      elsif ($macro eq 'AC_CANONICAL_HOST')
-	{
-	  if ($seen_canonical <= AC_CANONICAL_HOST)
-	    {
-	      $seen_canonical = AC_CANONICAL_HOST;
-	    }
-	}
-      elsif ($macro eq 'AC_CANONICAL_TARGET')
-	{
-	  $seen_canonical = AC_CANONICAL_TARGET;
-	}
-      elsif ($macro eq 'AC_CONFIG_AUX_DIR')
-	{
-	  if ($seen_init_automake)
-	    {
-	      error ($where, "AC_CONFIG_AUX_DIR must be called before "
-		     . "AM_INIT_AUTOMAKE ...", partial => 1);
-	      error ($seen_init_automake, "... AM_INIT_AUTOMAKE called here");
-	    }
-	  $config_aux_dir = $args[1];
-	  $config_aux_dir_set_in_configure_ac = 1;
-	  check_directory ($config_aux_dir, $where);
-	}
-      elsif ($macro eq 'AC_CONFIG_FILES')
-	{
-	  # Look at potential Makefile.am's.
-	  scan_autoconf_config_files ($where, $args[1]);
-	}
-      elsif ($macro eq 'AC_CONFIG_HEADERS')
-	{
-	  foreach my $spec (split (' ', $args[1]))
-	    {
-	      my ($dest, @src) = split (':', $spec);
-	      $ac_config_files_location{$dest} = $where;
-	      push @config_headers, $spec;
-	    }
-	}
-      elsif ($macro eq 'AC_CONFIG_LIBOBJ_DIR')
-	{
-	  $config_libobj_dir = $args[1];
-	  check_directory ($config_libobj_dir, $where);
-	}
-      elsif ($macro eq 'AC_CONFIG_LINKS')
-	{
-	  foreach my $spec (split (' ', $args[1]))
-	    {
-	      my ($dest, $src) = split (':', $spec);
-	      $ac_config_files_location{$dest} = $where;
-	      push @config_links, $spec;
-	    }
-	}
-      elsif ($macro eq 'AC_FC_SRCEXT')
-	{
-	  my $suffix = $args[1];
-	  # These flags are used as %SOURCEFLAG% in depend2.am,
-	  # where the trailing space is important.
-	  $sourceflags{'.' . $suffix} = '$(FCFLAGS_' . $suffix . ') '
-	    if ($suffix eq 'f90' || $suffix eq 'f95' || $suffix eq 'f03' || $suffix eq 'f08');
-	}
-      elsif ($macro eq 'AC_INIT')
-	{
-	  if (defined $args[2])
-	    {
-	      $package_version = $args[2];
-	      $package_version_location = $where;
-	    }
-	}
-      elsif ($macro eq 'AC_LIBSOURCE')
-	{
-	  $libsources{$args[1]} = $here;
-	}
-      elsif ($macro eq 'AC_REQUIRE_AUX_FILE')
-	{
-	  # Only remember the first time a file is required.
-	  $required_aux_file{$args[1]} = $where
-	    unless exists $required_aux_file{$args[1]};
-	}
-      elsif ($macro eq 'AC_SUBST_TRACE')
-	{
-	  # Just check for alphanumeric in AC_SUBST_TRACE.  If you do
-	  # AC_SUBST(5), then too bad.
-	  $configure_vars{$args[1]} = $where
-	    if $args[1] =~ /^\w+$/;
-	}
-      elsif ($macro eq 'AM_AUTOMAKE_VERSION')
-	{
-	  error ($where,
-		 "version mismatch.  This is Automake $VERSION,\n" .
-		 "but the definition used by this AM_INIT_AUTOMAKE\n" .
-		 "comes from Automake $args[1].  You should recreate\n" .
-		 "aclocal.m4 with aclocal and run automake again.\n",
-		 # $? = 63 is used to indicate version mismatch to missing.
-		 exit_code => 63)
-	    if $VERSION ne $args[1];
-
-	  $seen_automake_version = 1;
-	}
-      elsif ($macro eq 'AM_PROG_MKDIR_P')
-	{
-	  msg 'obsolete', $where, <<'EOF';
-The 'AM_PROG_MKDIR_P' macro is deprecated, and its use is discouraged.
-You should use the Autoconf-provided 'AC_PROG_MKDIR_P' macro instead,
-and use '$(MKDIR_P)' instead of '$(mkdir_p)'in your Makefile.am files.
-EOF
-	}
-      elsif ($macro eq 'AM_CONDITIONAL')
-	{
-	  $configure_cond{$args[1]} = $where;
-	}
-      elsif ($macro eq 'AM_EXTRA_RECURSIVE_TARGETS')
-	{
-          # Empty leading/trailing fields might be produced by split,
-          # hence the grep is really needed.
-          push @extra_recursive_targets,
-               grep (/./, (split /\s+/, $args[1]));
-	}
-      elsif ($macro eq 'AM_GNU_GETTEXT')
-	{
-	  $seen_gettext = $where;
-	  $ac_gettext_location = $where;
-	  $seen_gettext_external = grep ($_ eq 'external', @args);
-	}
-      elsif ($macro eq 'AM_GNU_GETTEXT_INTL_SUBDIR')
-	{
-	  $seen_gettext_intl = $where;
-	}
-      elsif ($macro eq 'AM_INIT_AUTOMAKE')
-	{
-	  $seen_init_automake = $where;
-	  if (defined $args[2])
-	    {
-              msg 'obsolete', $where, <<'EOF';
-AM_INIT_AUTOMAKE: two- and three-arguments forms are deprecated.  For more info, see:
-https://www.gnu.org/software/automake/manual/automake.html#Modernize-AM_005fINIT_005fAUTOMAKE-invocation
-EOF
-	      $package_version = $args[2];
-	      $package_version_location = $where;
-	    }
-	  elsif (defined $args[1])
-	    {
-	      my @opts = split (' ', $args[1]);
-	      @opts = map { { option => $_, where => $where } } @opts;
-	      exit $exit_code unless process_global_option_list (@opts);
-	    }
-	}
-      elsif ($macro eq 'AM_MAINTAINER_MODE')
-	{
-	  $seen_maint_mode = $where;
-	}
-      elsif ($macro eq 'AM_PROG_AR')
-	{
-	  $seen_ar = $where;
-	}
-      elsif ($macro eq '_AM_COND_IF')
-        {
-	  cond_stack_if ('', $args[1], $where);
-	  error ($where, "missing m4 quoting, macro depth $depth")
-	    if ($depth != 1);
-	}
-      elsif ($macro eq '_AM_COND_ELSE')
-        {
-	  cond_stack_else ('!', $args[1], $where);
-	  error ($where, "missing m4 quoting, macro depth $depth")
-	    if ($depth != 1);
-	}
-      elsif ($macro eq '_AM_COND_ENDIF')
-        {
-	  cond_stack_endif (undef, undef, $where);
-	  error ($where, "missing m4 quoting, macro depth $depth")
-	    if ($depth != 1);
-	}
-      elsif ($macro eq '_AM_SUBST_NOTMAKE')
-	{
-	  $ignored_configure_vars{$args[1]} = $where;
-	}
-      elsif ($macro eq 'm4_include'
-	     || $macro eq 'm4_sinclude'
-	     || $macro eq 'sinclude')
-	{
-	  # Skip missing 'sinclude'd files.
-	  next if $macro ne 'm4_include' && ! -f $args[1];
-
-	  # Some modified versions of Autoconf don't use
-	  # frozen files.  Consequently it's possible that we see all
-	  # m4_include's performed during Autoconf's startup.
-	  # Obviously we don't want to distribute Autoconf's files
-	  # so we skip absolute filenames here.
-	  push @configure_deps, '$(top_srcdir)/' . $args[1]
-	    unless $here =~ m,^(?:\w:)?[\\/],;
-	  # Keep track of the greatest timestamp.
-	  if (-e $args[1])
-	    {
-	      my $mtime = mtime $args[1];
-	      $configure_deps_greatest_timestamp = $mtime
-		if $mtime > $configure_deps_greatest_timestamp;
-	    }
-	}
-      elsif ($macro eq 'LT_SUPPORTED_TAG')
-	{
-	  $libtool_tags{$args[1]} = 1;
-	  $libtool_new_api = 1;
-	}
-      elsif ($macro eq '_LT_AC_TAGCONFIG')
-	{
-	  # _LT_AC_TAGCONFIG is an old macro present in Libtool 1.5.
-	  # We use it to detect whether tags are supported.  Our
-	  # preferred interface is LT_SUPPORTED_TAG, but it was
-	  # introduced in Libtool 1.6.
-	  if (0 == keys %libtool_tags)
-	    {
-	      # Hardcode the tags supported by Libtool 1.5.
-	      %libtool_tags = (CC => 1, CXX => 1, GCJ => 1, F77 => 1);
-	    }
-	}
-    }
-
-  error ($where, "condition stack not properly closed")
-    if (@cond_stack);
-
-  $tracefh->close;
-}
-
-
-# Check whether we use 'configure.ac' or 'configure.in'.
-# Scan it (and possibly 'aclocal.m4') for interesting things.
-# We must scan aclocal.m4 because there might be AC_SUBSTs and such there.
-sub scan_autoconf_files ()
-{
-  # Reinitialize libsources here.  This isn't really necessary,
-  # since we currently assume there is only one configure.ac.  But
-  # that won't always be the case.
-  %libsources = ();
-
-  # Keep track of the youngest configure dependency.
-  $configure_deps_greatest_timestamp = mtime $configure_ac;
-  if (-e 'aclocal.m4')
-    {
-      my $mtime = mtime 'aclocal.m4';
-      $configure_deps_greatest_timestamp = $mtime
-	if $mtime > $configure_deps_greatest_timestamp;
-    }
-
-  scan_autoconf_traces ($configure_ac);
-
-  @configure_input_files = sort keys %make_list;
-  # Set input and output files if not specified by user.
-  if (! @input_files)
-    {
-      @input_files = @configure_input_files;
-      %output_files = %make_list;
-    }
-
-
-  if (! $seen_init_automake)
-    {
-      err_ac ("no proper invocation of AM_INIT_AUTOMAKE was found.\nYou "
-	      . "should verify that $configure_ac invokes AM_INIT_AUTOMAKE,"
-	      . "\nthat aclocal.m4 is present in the top-level directory,\n"
-	      . "and that aclocal.m4 was recently regenerated "
-	      . "(using aclocal)");
-    }
-  else
-    {
-      if (! $seen_automake_version)
-	{
-	  if (-f 'aclocal.m4')
-	    {
-	      error ($seen_init_automake,
-		     "your implementation of AM_INIT_AUTOMAKE comes from " .
-		     "an\nold Automake version.  You should recreate " .
-		     "aclocal.m4\nwith aclocal and run automake again",
-		     # $? = 63 is used to indicate version mismatch to missing.
-		     exit_code => 63);
-	    }
-	  else
-	    {
-	      error ($seen_init_automake,
-		     "no proper implementation of AM_INIT_AUTOMAKE was " .
-		     "found,\nprobably because aclocal.m4 is missing.\n" .
-		     "You should run aclocal to create this file, then\n" .
-		     "run automake again");
-	    }
-	}
-    }
-
-  locate_aux_dir ();
-
-  # Look for some files we need.  Always check for these.  This
-  # check must be done for every run, even those where we are only
-  # looking at a subdir Makefile.  We must set relative_dir for
-  # push_required_file to work.
-  # Sort the files for stable verbose output.
-  $relative_dir = '.';
-  foreach my $file (sort keys %required_aux_file)
-    {
-      require_conf_file ($required_aux_file{$file}->get, FOREIGN, $file)
-    }
-  err_am "'install.sh' is an anachronism; use 'install-sh' instead"
-    if -f $config_aux_dir . '/install.sh';
-
-  # Preserve dist_common for later.
-  @configure_dist_common = @dist_common;
-}
-
-
-################################################################
-
 
 ## ------------------------ ##
 ## Handling the variables.  ##
@@ -5650,7 +4709,7 @@ parse_arguments;
 $configure_ac = require_configure_ac;
 
 # Do configure.ac scan only once.
-scan_autoconf_files;
+scan_autoconf_files (($ENV{AUTOCONF} || '@am_AUTOCONF@') . " ");
 
 if (! @input_files)
   {
diff --git a/lib/Automake/Global.pm b/lib/Automake/Global.pm
index f382aa35a..c04406133 100644
--- a/lib/Automake/Global.pm
+++ b/lib/Automake/Global.pm
@@ -33,10 +33,9 @@ use vars qw (@EXPORT);
     $seen_gettext $seen_gettext_external $seen_gettext_intl
     @extra_recursive_targets %libtool_tags $libtool_new_api $package_version
     $seen_ar %required_aux_file $seen_init_automake $seen_automake_version
-    @configure_deps $configure_deps_greatest_timestamp %configure_cond
-    %extension_map @configure_dist_common %languages %link_languages
-    %sourceflags %required_targets $am_file $configure_ac $ac_gettext_location
-    $package_version_location $required_conf_file_queue
+    %configure_cond %extension_map @configure_dist_common %languages
+    %link_languages %sourceflags %required_targets $am_file $configure_ac
+    $ac_gettext_location $package_version_location $required_conf_file_queue
     $output_deps_greatest_timestamp $output_all $output_header $output_rules
     $output_trailer @include_stack @all @check @check_tests %clean_files
     %compile_clean_files %libtool_clean_directories @sources @dist_sources
@@ -252,12 +251,6 @@ our $seen_init_automake = 0;
 # TRUE if we've seen AM_AUTOMAKE_VERSION.
 our $seen_automake_version = 0;
 
-# Files included by $configure_ac.
-our @configure_deps = ();
-
-# Greatest timestamp of configure's dependencies.
-our $configure_deps_greatest_timestamp = 0;
-
 # Hash table of AM_CONDITIONAL variables seen in configure.
 our %configure_cond = ();
 
diff --git a/lib/Automake/HandleConfigure.pm b/lib/Automake/HandleConfigure.pm
new file mode 100644
index 000000000..3b7e70780
--- /dev/null
+++ b/lib/Automake/HandleConfigure.pm
@@ -0,0 +1,856 @@
+# Copyright (C) 2018  Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package Automake::HandleConfigure;
+
+use 5.006;
+use strict;
+
+use Automake::Channels;
+use Automake::ChannelDefs;
+use Automake::Condition qw (TRUE FALSE);
+use Automake::CondStack;
+use Automake::Config;
+use Automake::ConfVars;
+use Automake::Errors;
+use Automake::File;
+use Automake::FileUtils;
+use Automake::Global;
+use Automake::Requires;
+use Automake::Location;
+use Automake::Options;
+use Automake::RuleDef;
+use Automake::SilentRules;
+use Automake::Utils;
+use Automake::Variable;
+use Automake::XFile;
+use Exporter 'import';
+use File::Basename;
+
+use vars qw (@EXPORT);
+
+@EXPORT = qw ($configure_deps_greatest_timestamp &handle_configure
+    &split_config_file_spec &scan_autoconf_config_files &scan_autoconf_files
+    &scan_aclocal_m4);
+
+# Helper functions for handling configure files inside Automake
+
+# Greatest timestamp of configure's dependencies.
+our $configure_deps_greatest_timestamp = 0;
+
+# Files included by $configure_ac.
+my @configure_deps = ();
+
+my %make_list;
+
+
+# ($REGEN, @DEPENDENCIES)
+# scan_aclocal_m4
+# ---------------
+# If aclocal.m4 creation is automated, return the list of its dependencies.
+sub scan_aclocal_m4 ()
+{
+  my $regen_aclocal = 0;
+
+  set_seen 'CONFIG_STATUS_DEPENDENCIES';
+  set_seen 'CONFIGURE_DEPENDENCIES';
+
+  if (-f 'aclocal.m4')
+    {
+      define_variable ("ACLOCAL_M4", '$(top_srcdir)/aclocal.m4', INTERNAL);
+
+      my $aclocal = new Automake::XFile "< aclocal.m4";
+      my $line = $aclocal->getline;
+      $regen_aclocal = $line =~ 'generated automatically by aclocal';
+    }
+
+  my @ac_deps = ();
+
+  if (set_seen ('ACLOCAL_M4_SOURCES'))
+    {
+      push (@ac_deps, '$(ACLOCAL_M4_SOURCES)');
+      msg_var ('obsolete', 'ACLOCAL_M4_SOURCES',
+	       "'ACLOCAL_M4_SOURCES' is obsolete.\n"
+	       . "It should be safe to simply remove it");
+    }
+
+  # Note that it might be possible that aclocal.m4 doesn't exist but
+  # should be auto-generated.  This case probably isn't very
+  # important.
+
+  return ($regen_aclocal, @ac_deps);
+}
+
+
+# handle_configure ($MAKEFILE_AM, $MAKEFILE_IN, $MAKEFILE, @INPUTS)
+# -----------------------------------------------------------------
+# Handle remaking and configure stuff.
+# We need the name of the input file, to do proper remaking rules.
+sub handle_configure
+{
+  my ($makefile_am, $makefile_in, $makefile, @inputs) = @_;
+
+  prog_error 'empty @inputs'
+    unless @inputs;
+
+  my ($rel_makefile_am, $rel_makefile_in) = prepend_srcdir ($makefile_am,
+							    $makefile_in);
+  my $rel_makefile = basename $makefile;
+
+  my $colon_infile = ':' . join (':', @inputs);
+  $colon_infile = '' if $colon_infile eq ":$makefile.in";
+  my @rewritten = rewrite_inputs_into_dependencies ($makefile, @inputs);
+  my ($regen_aclocal_m4, @aclocal_m4_deps) = scan_aclocal_m4;
+  define_pretty_variable ('am__aclocal_m4_deps', TRUE, INTERNAL,
+			  @configure_deps, @aclocal_m4_deps,
+			  '$(top_srcdir)/' . $configure_ac);
+  my @configuredeps = ('$(am__aclocal_m4_deps)', '$(CONFIGURE_DEPENDENCIES)');
+  push @configuredeps, '$(ACLOCAL_M4)' if -f 'aclocal.m4';
+  define_pretty_variable ('am__configure_deps', TRUE, INTERNAL,
+			  @configuredeps);
+
+  my $automake_options = '--' . $strictness_name .
+			 (global_option 'no-dependencies' ? ' --ignore-deps' : '');
+
+  $output_rules .= file_contents
+    ('configure',
+     new Automake::Location,
+     MAKEFILE              => $rel_makefile,
+     'MAKEFILE-DEPS'       => "@rewritten",
+     'CONFIG-MAKEFILE'     => ($relative_dir eq '.') ? '$@' : '$(subdir)/$@',
+     'MAKEFILE-IN'         => $rel_makefile_in,
+     'HAVE-MAKEFILE-IN-DEPS' => (@include_stack > 0),
+     'MAKEFILE-IN-DEPS'    => "@include_stack",
+     'MAKEFILE-AM'         => $rel_makefile_am,
+     'AUTOMAKE-OPTIONS'    => $automake_options,
+     'MAKEFILE-AM-SOURCES' => "$makefile$colon_infile",
+     'REGEN-ACLOCAL-M4'    => $regen_aclocal_m4,
+     VERBOSE               => verbose_flag ('GEN'));
+
+  if ($relative_dir eq '.')
+    {
+      push_dist_common ('acconfig.h')
+	if -f 'acconfig.h';
+    }
+
+  # If we have a configure header, require it.
+  my $hdr_index = 0;
+  my @distclean_config;
+  foreach my $spec (@config_headers)
+    {
+      $hdr_index += 1;
+      # $CONFIG_H_PATH: config.h from top level.
+      my ($config_h_path, @ins) = split_config_file_spec ($spec);
+      my $config_h_dir = dirname ($config_h_path);
+
+      # If the header is in the current directory we want to build
+      # the header here.  Otherwise, if we're at the topmost
+      # directory and the header's directory doesn't have a
+      # Makefile, then we also want to build the header.
+      if ($relative_dir eq $config_h_dir
+	  || ($relative_dir eq '.' && ! is_make_dir ($config_h_dir)))
+	{
+	  my ($cn_sans_dir, $stamp_dir);
+	  if ($relative_dir eq $config_h_dir)
+	    {
+	      $cn_sans_dir = basename ($config_h_path);
+	      $stamp_dir = '';
+	    }
+	  else
+	    {
+	      $cn_sans_dir = $config_h_path;
+	      if ($config_h_dir eq '.')
+		{
+		  $stamp_dir = '';
+		}
+	      else
+		{
+		  $stamp_dir = $config_h_dir . '/';
+		}
+	    }
+
+	  # This will also distribute all inputs.
+	  @ins = rewrite_inputs_into_dependencies ($config_h_path, @ins);
+
+	  # Cannot define rebuild rules for filenames with shell variables.
+	  next if (substitute_ac_subst_variables $config_h_path) =~ /\$/;
+
+	  # Header defined in this directory.
+	  my @files;
+	  if (-f $config_h_path . '.top')
+	    {
+	      push (@files, "$cn_sans_dir.top");
+	    }
+	  if (-f $config_h_path . '.bot')
+	    {
+	      push (@files, "$cn_sans_dir.bot");
+	    }
+
+	  push_dist_common (@files);
+
+	  # For now, acconfig.h can only appear in the top srcdir.
+	  if (-f 'acconfig.h')
+	    {
+	      push (@files, '$(top_srcdir)/acconfig.h');
+	    }
+
+	  my $stamp = "${stamp_dir}stamp-h${hdr_index}";
+	  $output_rules .=
+	    file_contents ('remake-hdr',
+			   new Automake::Location,
+			   FILES            => "@files",
+			   'FIRST-HDR'      => ($hdr_index == 1),
+			   CONFIG_H         => $cn_sans_dir,
+			   CONFIG_HIN       => $ins[0],
+			   CONFIG_H_DEPS    => "@ins",
+			   CONFIG_H_PATH    => $config_h_path,
+			   STAMP            => "$stamp");
+
+	  push @distclean_config, $cn_sans_dir, $stamp;
+	}
+    }
+
+  $output_rules .= file_contents ('clean-hdr',
+				  new Automake::Location,
+				  FILES => "@distclean_config")
+    if @distclean_config;
+
+  # Distribute and define mkinstalldirs only if it is already present
+  # in the package, for backward compatibility (some people may still
+  # use $(mkinstalldirs)).
+  # TODO: start warning about this in Automake 1.14, and have
+  # TODO: Automake 2.0 drop it (and the mkinstalldirs script
+  # TODO: as well).
+  my $mkidpath = "$config_aux_dir/mkinstalldirs";
+  if (-f $mkidpath)
+    {
+      # Use require_file so that any existing script gets updated
+      # by --force-missing.
+      require_conf_file ($mkidpath, FOREIGN, 'mkinstalldirs');
+      define_variable ('mkinstalldirs',
+		       "\$(SHELL) $am_config_aux_dir/mkinstalldirs", INTERNAL);
+    }
+  else
+    {
+      # Use $(install_sh), not $(MKDIR_P) because the latter requires
+      # at least one argument, and $(mkinstalldirs) used to work
+      # even without arguments (e.g. $(mkinstalldirs) $(conditional_dir)).
+      define_variable ('mkinstalldirs', '$(install_sh) -d', INTERNAL);
+    }
+
+  reject_var ('CONFIG_HEADER',
+	      "'CONFIG_HEADER' is an anachronism; now determined "
+	      . "automatically\nfrom '$configure_ac'");
+
+  my @config_h;
+  foreach my $spec (@config_headers)
+    {
+      my ($out, @ins) = split_config_file_spec ($spec);
+      # Generate CONFIG_HEADER define.
+      if ($relative_dir eq dirname ($out))
+	{
+	  push @config_h, basename ($out);
+	}
+      else
+	{
+	  push @config_h, "\$(top_builddir)/$out";
+	}
+    }
+  define_variable ("CONFIG_HEADER", "@config_h", INTERNAL)
+    if @config_h;
+
+  # Now look for other files in this directory which must be remade
+  # by config.status, and generate rules for them.
+  my @actual_other_files = ();
+  # These get cleaned only in a VPATH build.
+  my @actual_other_vpath_files = ();
+  foreach my $lfile (@other_input_files)
+    {
+      my $file;
+      my @inputs;
+      if ($lfile =~ /^([^:]*):(.*)$/)
+	{
+	  # This is the ":" syntax of AC_OUTPUT.
+	  $file = $1;
+	  @inputs = split (':', $2);
+	}
+      else
+	{
+	  # Normal usage.
+	  $file = $lfile;
+	  @inputs = $file . '.in';
+	}
+
+      # Automake files should not be stored in here, but in %MAKE_LIST.
+      prog_error ("$lfile in \@other_input_files\n"
+		  . "\@other_input_files = (@other_input_files)")
+	if -f $file . '.am';
+
+      my $local = basename ($file);
+
+      # We skip files that aren't in this directory.  However, if
+      # the file's directory does not have a Makefile, and we are
+      # currently doing '.', then we create a rule to rebuild the
+      # file in the subdir.
+      my $fd = dirname ($file);
+      if ($fd ne $relative_dir)
+	{
+	  if ($relative_dir eq '.' && ! is_make_dir ($fd))
+	    {
+	      $local = $file;
+	    }
+	  else
+	    {
+	      next;
+	    }
+	}
+
+      my @rewritten_inputs = rewrite_inputs_into_dependencies ($file, @inputs);
+
+      # Cannot output rules for shell variables.
+      next if (substitute_ac_subst_variables $local) =~ /\$/;
+
+      my $condstr = '';
+      my $cond = $ac_config_files_condition{$lfile};
+      if (defined $cond)
+        {
+	  $condstr = $cond->subst_string;
+	  Automake::Rule::define ($local, $configure_ac, RULE_AUTOMAKE, $cond,
+				  $ac_config_files_location{$file});
+        }
+      $output_rules .= ($condstr . $local . ': '
+			. '$(top_builddir)/config.status '
+			. "@rewritten_inputs\n"
+			. $condstr . "\t"
+			. 'cd $(top_builddir) && '
+			. '$(SHELL) ./config.status '
+			. ($relative_dir eq '.' ? '' : '$(subdir)/')
+			. '$@'
+			. "\n");
+      push (@actual_other_files, $local);
+    }
+
+  # For links we should clean destinations and distribute sources.
+  foreach my $spec (@config_links)
+    {
+      my ($link, $file) = split /:/, $spec;
+      # Some people do AC_CONFIG_LINKS($computed).  We only handle
+      # the DEST:SRC form.
+      next unless $file;
+      my $where = $ac_config_files_location{$link};
+
+      # Skip destinations that contain shell variables.
+      if ((substitute_ac_subst_variables $link) !~ /\$/)
+	{
+	  # We skip links that aren't in this directory.  However, if
+	  # the link's directory does not have a Makefile, and we are
+	  # currently doing '.', then we add the link to CONFIG_CLEAN_FILES
+	  # in '.'s Makefile.in.
+	  my $local = basename ($link);
+	  my $fd = dirname ($link);
+	  if ($fd ne $relative_dir)
+	    {
+	      if ($relative_dir eq '.' && ! is_make_dir ($fd))
+		{
+		  $local = $link;
+		}
+	      else
+		{
+		  $local = undef;
+		}
+	    }
+	  if ($file ne $link)
+	    {
+	      push @actual_other_files, $local if $local;
+	    }
+	  else
+	    {
+	      push @actual_other_vpath_files, $local if $local;
+	    }
+	}
+
+      # Do not process sources that contain shell variables.
+      if ((substitute_ac_subst_variables $file) !~ /\$/)
+	{
+	  my $fd = dirname ($file);
+
+	  # We distribute files that are in this directory.
+	  # At the top-level ('.') we also distribute files whose
+	  # directory does not have a Makefile.
+	  if (($fd eq $relative_dir)
+	      || ($relative_dir eq '.' && ! is_make_dir ($fd)))
+	    {
+	      # The following will distribute $file as a side-effect when
+	      # it is appropriate (i.e., when $file is not already an output).
+	      # We do not need the result, just the side-effect.
+	      rewrite_inputs_into_dependencies ($link, $file);
+	    }
+	}
+    }
+
+  # These files get removed by "make distclean".
+  define_pretty_variable ('CONFIG_CLEAN_FILES', TRUE, INTERNAL,
+			  @actual_other_files);
+  define_pretty_variable ('CONFIG_CLEAN_VPATH_FILES', TRUE, INTERNAL,
+			  @actual_other_vpath_files);
+}
+
+
+# ($OUTPUT, @INPUTS)
+# split_config_file_spec ($SPEC)
+# ------------------------------
+# Decode the Autoconf syntax for config files (files, headers, links
+# etc.).
+sub split_config_file_spec
+{
+  my ($spec) = @_;
+  my ($output, @inputs) = split (/:/, $spec);
+
+  push @inputs, "$output.in"
+    unless @inputs;
+
+  return ($output, @inputs);
+}
+
+
+# scan_autoconf_config_files ($WHERE, $CONFIG-FILES)
+# --------------------------------------------------
+# Study $CONFIG-FILES which is the first argument to AC_CONFIG_FILES
+# (or AC_OUTPUT).
+sub scan_autoconf_config_files
+{
+  my ($where, $config_files) = @_;
+
+  # Look at potential Makefile.am's.
+  foreach (split ' ', $config_files)
+    {
+      # Must skip empty string for Perl 4.
+      next if $_ eq "\\" || $_ eq '';
+
+      # Handle $local:$input syntax.
+      my ($local, @rest) = split (/:/);
+      @rest = ("$local.in",) unless @rest;
+      # Keep in sync with test 'conffile-leading-dot.sh'.
+      msg ('unsupported', $where,
+           "omit leading './' from config file names such as '$local';"
+           . "\nremake rules might be subtly broken otherwise")
+        if ($local =~ /^\.\//);
+      my $input = locate_am @rest;
+      if ($input)
+	{
+	  # We have a file that automake should generate.
+	  $make_list{$input} = join (':', ($local, @rest));
+	}
+      else
+	{
+	  # We have a file that automake should cause to be
+	  # rebuilt, but shouldn't generate itself.
+	  push (@other_input_files, $_);
+	}
+      $ac_config_files_location{$local} = $where;
+      $ac_config_files_condition{$local} =
+        new Automake::Condition (@cond_stack)
+          if (@cond_stack);
+    }
+}
+
+
+sub scan_autoconf_traces
+{
+  my ($filename, $traces) = @_;
+
+  # Macros to trace, with their minimal number of arguments.
+  #
+  # IMPORTANT: If you add a macro here, you should also add this macro
+  # =========  to Automake-preselection in autoconf/lib/autom4te.in.
+  my %traced = (
+		AC_CANONICAL_BUILD => 0,
+		AC_CANONICAL_HOST => 0,
+		AC_CANONICAL_TARGET => 0,
+		AC_CONFIG_AUX_DIR => 1,
+		AC_CONFIG_FILES => 1,
+		AC_CONFIG_HEADERS => 1,
+		AC_CONFIG_LIBOBJ_DIR => 1,
+		AC_CONFIG_LINKS => 1,
+		AC_FC_SRCEXT => 1,
+		AC_INIT => 0,
+		AC_LIBSOURCE => 1,
+		AC_REQUIRE_AUX_FILE => 1,
+		AC_SUBST_TRACE => 1,
+		AM_AUTOMAKE_VERSION => 1,
+                AM_PROG_MKDIR_P => 0,
+		AM_CONDITIONAL => 2,
+		AM_EXTRA_RECURSIVE_TARGETS => 1,
+		AM_GNU_GETTEXT => 0,
+		AM_GNU_GETTEXT_INTL_SUBDIR => 0,
+		AM_INIT_AUTOMAKE => 0,
+		AM_MAINTAINER_MODE => 0,
+		AM_PROG_AR => 0,
+		_AM_SUBST_NOTMAKE => 1,
+		_AM_COND_IF => 1,
+		_AM_COND_ELSE => 1,
+		_AM_COND_ENDIF => 1,
+		LT_SUPPORTED_TAG => 1,
+		_LT_AC_TAGCONFIG => 0,
+		m4_include => 1,
+		m4_sinclude => 1,
+		sinclude => 1,
+	      );
+
+  # Use a separator unlikely to be used, not ':', the default, which
+  # has a precise meaning for AC_CONFIG_FILES and so on.
+  $traces .= join (' ',
+		   map { "--trace=$_" . ':\$f:\$l::\$d::\$n::\${::}%' }
+		   (keys %traced));
+
+  my $tracefh = new Automake::XFile ("$traces $filename |");
+  verb "reading $traces";
+
+  @cond_stack = ();
+  my $where;
+
+  while ($_ = $tracefh->getline)
+    {
+      chomp;
+      my ($here, $depth, @args) = split (/::/);
+      $where = new Automake::Location $here;
+      my $macro = $args[0];
+
+      prog_error ("unrequested trace '$macro'")
+	unless exists $traced{$macro};
+
+      # Skip and diagnose malformed calls.
+      if ($#args < $traced{$macro})
+	{
+	  msg ('syntax', $where, "not enough arguments for $macro");
+	  next;
+	}
+
+      # Alphabetical ordering please.
+      if ($macro eq 'AC_CANONICAL_BUILD')
+	{
+	  if ($seen_canonical <= AC_CANONICAL_BUILD)
+	    {
+	      $seen_canonical = AC_CANONICAL_BUILD;
+	    }
+	}
+      elsif ($macro eq 'AC_CANONICAL_HOST')
+	{
+	  if ($seen_canonical <= AC_CANONICAL_HOST)
+	    {
+	      $seen_canonical = AC_CANONICAL_HOST;
+	    }
+	}
+      elsif ($macro eq 'AC_CANONICAL_TARGET')
+	{
+	  $seen_canonical = AC_CANONICAL_TARGET;
+	}
+      elsif ($macro eq 'AC_CONFIG_AUX_DIR')
+	{
+	  if ($seen_init_automake)
+	    {
+	      error ($where, "AC_CONFIG_AUX_DIR must be called before "
+		     . "AM_INIT_AUTOMAKE ...", partial => 1);
+	      error ($seen_init_automake, "... AM_INIT_AUTOMAKE called here");
+	    }
+	  $config_aux_dir = $args[1];
+	  $config_aux_dir_set_in_configure_ac = 1;
+	  check_directory ($config_aux_dir, $where);
+	}
+      elsif ($macro eq 'AC_CONFIG_FILES')
+	{
+	  # Look at potential Makefile.am's.
+	  scan_autoconf_config_files ($where, $args[1]);
+	}
+      elsif ($macro eq 'AC_CONFIG_HEADERS')
+	{
+	  foreach my $spec (split (' ', $args[1]))
+	    {
+	      my ($dest, @src) = split (':', $spec);
+	      $ac_config_files_location{$dest} = $where;
+	      push @config_headers, $spec;
+	    }
+	}
+      elsif ($macro eq 'AC_CONFIG_LIBOBJ_DIR')
+	{
+	  $config_libobj_dir = $args[1];
+	  check_directory ($config_libobj_dir, $where);
+	}
+      elsif ($macro eq 'AC_CONFIG_LINKS')
+	{
+	  foreach my $spec (split (' ', $args[1]))
+	    {
+	      my ($dest, $src) = split (':', $spec);
+	      $ac_config_files_location{$dest} = $where;
+	      push @config_links, $spec;
+	    }
+	}
+      elsif ($macro eq 'AC_FC_SRCEXT')
+	{
+	  my $suffix = $args[1];
+	  # These flags are used as %SOURCEFLAG% in depend2.am,
+	  # where the trailing space is important.
+	  $sourceflags{'.' . $suffix} = '$(FCFLAGS_' . $suffix . ') '
+	    if ($suffix eq 'f90' || $suffix eq 'f95' || $suffix eq 'f03' || $suffix eq 'f08');
+	}
+      elsif ($macro eq 'AC_INIT')
+	{
+	  if (defined $args[2])
+	    {
+	      $package_version = $args[2];
+	      $package_version_location = $where;
+	    }
+	}
+      elsif ($macro eq 'AC_LIBSOURCE')
+	{
+	  $libsources{$args[1]} = $here;
+	}
+      elsif ($macro eq 'AC_REQUIRE_AUX_FILE')
+	{
+	  # Only remember the first time a file is required.
+	  $required_aux_file{$args[1]} = $where
+	    unless exists $required_aux_file{$args[1]};
+	}
+      elsif ($macro eq 'AC_SUBST_TRACE')
+	{
+	  # Just check for alphanumeric in AC_SUBST_TRACE.  If you do
+	  # AC_SUBST(5), then too bad.
+	  $configure_vars{$args[1]} = $where
+	    if $args[1] =~ /^\w+$/;
+	}
+      elsif ($macro eq 'AM_AUTOMAKE_VERSION')
+	{
+	  error ($where,
+		 "version mismatch.  This is Automake $VERSION,\n" .
+		 "but the definition used by this AM_INIT_AUTOMAKE\n" .
+		 "comes from Automake $args[1].  You should recreate\n" .
+		 "aclocal.m4 with aclocal and run automake again.\n",
+		 # $? = 63 is used to indicate version mismatch to missing.
+		 exit_code => 63)
+	    if $VERSION ne $args[1];
+
+	  $seen_automake_version = 1;
+	}
+      elsif ($macro eq 'AM_PROG_MKDIR_P')
+	{
+	  msg 'obsolete', $where, <<'EOF';
+The 'AM_PROG_MKDIR_P' macro is deprecated, and its use is discouraged.
+You should use the Autoconf-provided 'AC_PROG_MKDIR_P' macro instead,
+and use '$(MKDIR_P)' instead of '$(mkdir_p)'in your Makefile.am files.
+EOF
+	}
+      elsif ($macro eq 'AM_CONDITIONAL')
+	{
+	  $configure_cond{$args[1]} = $where;
+	}
+      elsif ($macro eq 'AM_EXTRA_RECURSIVE_TARGETS')
+	{
+          # Empty leading/trailing fields might be produced by split,
+          # hence the grep is really needed.
+          push @extra_recursive_targets,
+               grep (/./, (split /\s+/, $args[1]));
+	}
+      elsif ($macro eq 'AM_GNU_GETTEXT')
+	{
+	  $seen_gettext = $where;
+	  $ac_gettext_location = $where;
+	  $seen_gettext_external = grep ($_ eq 'external', @args);
+	}
+      elsif ($macro eq 'AM_GNU_GETTEXT_INTL_SUBDIR')
+	{
+	  $seen_gettext_intl = $where;
+	}
+      elsif ($macro eq 'AM_INIT_AUTOMAKE')
+	{
+	  $seen_init_automake = $where;
+	  if (defined $args[2])
+	    {
+              msg 'obsolete', $where, <<'EOF';
+AM_INIT_AUTOMAKE: two- and three-arguments forms are deprecated.  For more info, see:
+https://www.gnu.org/software/automake/manual/automake.html#Modernize-AM_005fINIT_005fAUTOMAKE-invocation
+EOF
+	      $package_version = $args[2];
+	      $package_version_location = $where;
+	    }
+	  elsif (defined $args[1])
+	    {
+	      my @opts = split (' ', $args[1]);
+	      @opts = map { { option => $_, where => $where } } @opts;
+	      exit $exit_code unless process_global_option_list (@opts);
+	    }
+	}
+      elsif ($macro eq 'AM_MAINTAINER_MODE')
+	{
+	  $seen_maint_mode = $where;
+	}
+      elsif ($macro eq 'AM_PROG_AR')
+	{
+	  $seen_ar = $where;
+	}
+      elsif ($macro eq '_AM_COND_IF')
+        {
+	  cond_stack_if ('', $args[1], $where);
+	  error ($where, "missing m4 quoting, macro depth $depth")
+	    if ($depth != 1);
+	}
+      elsif ($macro eq '_AM_COND_ELSE')
+        {
+	  cond_stack_else ('!', $args[1], $where);
+	  error ($where, "missing m4 quoting, macro depth $depth")
+	    if ($depth != 1);
+	}
+      elsif ($macro eq '_AM_COND_ENDIF')
+        {
+	  cond_stack_endif (undef, undef, $where);
+	  error ($where, "missing m4 quoting, macro depth $depth")
+	    if ($depth != 1);
+	}
+      elsif ($macro eq '_AM_SUBST_NOTMAKE')
+	{
+	  $ignored_configure_vars{$args[1]} = $where;
+	}
+      elsif ($macro eq 'm4_include'
+	     || $macro eq 'm4_sinclude'
+	     || $macro eq 'sinclude')
+	{
+	  # Skip missing 'sinclude'd files.
+	  next if $macro ne 'm4_include' && ! -f $args[1];
+
+	  # Some modified versions of Autoconf don't use
+	  # frozen files.  Consequently it's possible that we see all
+	  # m4_include's performed during Autoconf's startup.
+	  # Obviously we don't want to distribute Autoconf's files
+	  # so we skip absolute filenames here.
+	  push @configure_deps, '$(top_srcdir)/' . $args[1]
+	    unless $here =~ m,^(?:\w:)?[\\/],;
+	  # Keep track of the greatest timestamp.
+	  if (-e $args[1])
+	    {
+	      my $mtime = mtime $args[1];
+	      $configure_deps_greatest_timestamp = $mtime
+		if $mtime > $configure_deps_greatest_timestamp;
+	    }
+	}
+      elsif ($macro eq 'LT_SUPPORTED_TAG')
+	{
+	  $libtool_tags{$args[1]} = 1;
+	  $libtool_new_api = 1;
+	}
+      elsif ($macro eq '_LT_AC_TAGCONFIG')
+	{
+	  # _LT_AC_TAGCONFIG is an old macro present in Libtool 1.5.
+	  # We use it to detect whether tags are supported.  Our
+	  # preferred interface is LT_SUPPORTED_TAG, but it was
+	  # introduced in Libtool 1.6.
+	  if (0 == keys %libtool_tags)
+	    {
+	      # Hardcode the tags supported by Libtool 1.5.
+	      %libtool_tags = (CC => 1, CXX => 1, GCJ => 1, F77 => 1);
+	    }
+	}
+    }
+
+  error ($where, "condition stack not properly closed")
+    if (@cond_stack);
+
+  $tracefh->close;
+}
+
+
+# Check whether we use 'configure.ac' or 'configure.in'.
+# Scan it (and possibly 'aclocal.m4') for interesting things.
+# We must scan aclocal.m4 because there might be AC_SUBSTs and such there.
+sub scan_autoconf_files
+{
+  my ($traces) = @_;
+
+  # Reinitialize libsources here.  This isn't really necessary,
+  # since we currently assume there is only one configure.ac.  But
+  # that won't always be the case.
+  %libsources = ();
+
+  # Keep track of the youngest configure dependency.
+  $configure_deps_greatest_timestamp = mtime $configure_ac;
+  if (-e 'aclocal.m4')
+    {
+      my $mtime = mtime 'aclocal.m4';
+      $configure_deps_greatest_timestamp = $mtime
+	if $mtime > $configure_deps_greatest_timestamp;
+    }
+
+  scan_autoconf_traces ($configure_ac, $traces);
+
+  @configure_input_files = sort keys %make_list;
+  # Set input and output files if not specified by user.
+  if (! @input_files)
+    {
+      @input_files = @configure_input_files;
+      %output_files = %make_list;
+    }
+
+
+  if (! $seen_init_automake)
+    {
+      err_ac ("no proper invocation of AM_INIT_AUTOMAKE was found.\nYou "
+	      . "should verify that $configure_ac invokes AM_INIT_AUTOMAKE,"
+	      . "\nthat aclocal.m4 is present in the top-level directory,\n"
+	      . "and that aclocal.m4 was recently regenerated "
+	      . "(using aclocal)");
+    }
+  else
+    {
+      if (! $seen_automake_version)
+	{
+	  if (-f 'aclocal.m4')
+	    {
+	      error ($seen_init_automake,
+		     "your implementation of AM_INIT_AUTOMAKE comes from " .
+		     "an\nold Automake version.  You should recreate " .
+		     "aclocal.m4\nwith aclocal and run automake again",
+		     # $? = 63 is used to indicate version mismatch to missing.
+		     exit_code => 63);
+	    }
+	  else
+	    {
+	      error ($seen_init_automake,
+		     "no proper implementation of AM_INIT_AUTOMAKE was " .
+		     "found,\nprobably because aclocal.m4 is missing.\n" .
+		     "You should run aclocal to create this file, then\n" .
+		     "run automake again");
+	    }
+	}
+    }
+
+  locate_aux_dir ();
+
+  # Look for some files we need.  Always check for these.  This
+  # check must be done for every run, even those where we are only
+  # looking at a subdir Makefile.  We must set relative_dir for
+  # push_required_file to work.
+  # Sort the files for stable verbose output.
+  $relative_dir = '.';
+  foreach my $file (sort keys %required_aux_file)
+    {
+      require_conf_file ($required_aux_file{$file}->get, FOREIGN, $file)
+    }
+  err_am "'install.sh' is an anachronism; use 'install-sh' instead"
+    if -f $config_aux_dir . '/install.sh';
+
+  # Preserve dist_common for later.
+  @configure_dist_common = @dist_common;
+}
+
+
+1;
diff --git a/lib/Automake/Utils.pm b/lib/Automake/Utils.pm
index 65364f8ce..98c84e42b 100644
--- a/lib/Automake/Utils.pm
+++ b/lib/Automake/Utils.pm
@@ -18,6 +18,7 @@ package Automake::Utils;
 use 5.006;
 use strict;
 
+use Automake::Channels;
 use Automake::Global;
 use Automake::Location;
 use Automake::Options;
@@ -34,7 +35,9 @@ use vars qw (@EXPORT);
     $config_aux_dir_set_in_configure_ac $seen_maint_mode $relative_dir
     $seen_canonical $am_file_cache &var_SUFFIXES_trigger &locate_aux_dir
     &subst &make_paragraphs &flatten &canonicalize &push_dist_common
-    &is_make_dir &backname &get_number_of_threads &locate_am);
+    &is_make_dir &backname &get_number_of_threads &locate_am &prepend_srcdir
+    &rewrite_inputs_into_dependencies &substitute_ac_subst_variables
+    &check_directory);
 
 # Directory to search for configure-required files.  This
 # will be computed by locate_aux_dir() and can be set using
@@ -413,4 +416,140 @@ sub locate_am
 }
 
 
+# @DEPENDENCIES
+# prepend_srcdir (@INPUTS)
+# ------------------------
+# Prepend $(srcdir) or $(top_srcdir) to all @INPUTS.  The idea is that
+# if an input file has a directory part the same as the current
+# directory, then the directory part is simply replaced by $(srcdir).
+# But if the directory part is different, then $(top_srcdir) is
+# prepended.
+sub prepend_srcdir
+{
+  my (@inputs) = @_;
+  my @newinputs;
+
+  foreach my $single (@inputs)
+    {
+      if (dirname ($single) eq $relative_dir)
+	{
+	  push (@newinputs, '$(srcdir)/' . basename ($single));
+	}
+      else
+	{
+	  push (@newinputs, '$(top_srcdir)/' . $single);
+	}
+    }
+  return @newinputs;
+}
+
+
+# Helper function for 'substitute_ac_subst_variables'.
+sub substitute_ac_subst_variables_worker
+{
+  my ($token) = @_;
+  return "\@$token\@" if var $token;
+  return "\${$token\}";
+}
+
+
+# substitute_ac_subst_variables ($TEXT)
+# -------------------------------------
+# Replace any occurrence of ${FOO} in $TEXT by @FOO@ if FOO is an AC_SUBST
+# variable.
+sub substitute_ac_subst_variables
+{
+  my ($text) = @_;
+  $text =~ s/\$[{]([^ \t=:+{}]+)}/substitute_ac_subst_variables_worker ($1)/ge;
+  return $text;
+}
+
+
+# @DEPENDENCIES
+# rewrite_inputs_into_dependencies ($OUTPUT, @INPUTS)
+# ---------------------------------------------------
+# Compute a list of dependencies appropriate for the rebuild
+# rule of
+#   AC_CONFIG_FILES($OUTPUT:$INPUT[0]:$INPUTS[1]:...)
+# Also distribute $INPUTs which are not built by another AC_CONFIG_FOOs.
+sub rewrite_inputs_into_dependencies
+{
+  my ($file, @inputs) = @_;
+  my @res = ();
+
+  for my $i (@inputs)
+    {
+      # We cannot create dependencies on shell variables.
+      next if (substitute_ac_subst_variables $i) =~ /\$/;
+
+      if (exists $ac_config_files_location{$i} && $i ne $file)
+	{
+	  my $di = dirname $i;
+	  if ($di eq $relative_dir)
+	    {
+	      $i = basename $i;
+	    }
+	  # In the top-level Makefile we do not use $(top_builddir), because
+	  # we are already there, and since the targets are built without
+	  # a $(top_builddir), it helps BSD Make to match them with
+	  # dependencies.
+	  elsif ($relative_dir ne '.')
+	    {
+	      $i = '$(top_builddir)/' . $i;
+	    }
+	}
+      else
+	{
+	  msg ('error', $ac_config_files_location{$file},
+	       "required file '$i' not found")
+	    unless $i =~ /\$/ || exists $output_files{$i} || -f $i;
+	  ($i) = prepend_srcdir ($i);
+	  push_dist_common ($i);
+	}
+      push @res, $i;
+    }
+  return @res;
+}
+
+
+# check_directory ($NAME, $WHERE [, $RELATIVE_DIR = "."])
+# -------------------------------------------------------
+# Ensure $NAME is a directory (in $RELATIVE_DIR), and that it uses a sane
+# name.  Use $WHERE as a location in the diagnostic, if any.
+sub check_directory
+{
+  my ($dir, $where, $reldir) = @_;
+  $reldir = '.' unless defined $reldir;
+
+  error $where, "required directory $reldir/$dir does not exist"
+    unless -d "$reldir/$dir";
+
+  # If an 'obj/' directory exists, BSD make will enter it before
+  # reading 'Makefile'.  Hence the 'Makefile' in the current directory
+  # will not be read.
+  #
+  #  % cat Makefile
+  #  all:
+  #          echo Hello
+  #  % cat obj/Makefile
+  #  all:
+  #          echo World
+  #  % make      # GNU make
+  #  echo Hello
+  #  Hello
+  #  % pmake     # BSD make
+  #  echo World
+  #  World
+  msg ('portability', $where,
+       "naming a subdirectory 'obj' causes troubles with BSD make")
+    if $dir eq 'obj';
+
+  # 'aux' is probably the most important of the following forbidden name,
+  # since it's tempting to use it as an AC_CONFIG_AUX_DIR.
+  msg ('portability', $where,
+       "name '$dir' is reserved on W32 and DOS platforms")
+    if grep (/^\Q$dir\E$/i, qw/aux lpt1 lpt2 lpt3 com1 com2 com3 com4 con prn/);
+}
+
+
 1;
diff --git a/lib/Automake/local.mk b/lib/Automake/local.mk
index 46668c65f..c2e03cbe1 100644
--- a/lib/Automake/local.mk
+++ b/lib/Automake/local.mk
@@ -34,6 +34,7 @@ dist_perllib_DATA = \
   %D%/General.pm \
   %D%/Global.pm \
   %D%/Getopt.pm \
+  %D%/HandleConfigure.pm \
   %D%/Item.pm \
   %D%/ItemDef.pm \
   %D%/LangHandling.pm \