aclocal: more granularity in acdir overriding

Before this change, using the `--acdir' option caused aclocal to
redefine both the directory of automake-provided m4 macros and the
directory of third-party system-wide m4 macros.  With this change,
we deprecate the `--acdir' aclocal option, and introduce two new
options `--automake-acdir' and `--system-acdir', to allow for more
granularity.

* aclocal.in (@automake_includes, @system_includes,
@user_includes): Fix and extend comments.
(usage): Update.
(handle_acdir_option): New function.
(parse_arguments): Recognize new options `--system-acdir' and
`automake-acdir', and handle `--acdir' using the new function
above.  Simplify logic by assuming that the directory of
third-party system-wide m4 files always exists.
* tests/aclocal.in: Update to use the new options, instead of
the deprecated. `--acdir'.
* m4/dirlist: Move ...
* m4/acdir/dirlist: ... here.
* m4/Makefile.am (EXTRA_DIST): Update.
(m4datadir): Rename ...
(automake_acdir): ... to this.  Accordingly, ...
(dist_m4data_DATA): ... rename this ...
(dist_automake_ac_DATA): ... to this.
(system_acdir): New, directory.
(dist_system_ac_DATA): New, defined to an empty value; this will
ensure that the $(system_acdir) directory will be created by
"make install".
* tests/aclocal.test: Remove check about the `--print-ac-dir'
option of aclocal, it has been moved into ...
* tests/aclocal-print-acdir.test: ... this new test, and quite
extended.
* tests/aclocal-acdir.test: New test.
* tests/Makefile.am (TESTS): Add the new tests.
* NEWS, bootstrap: Update.
* doc/automake.texi (aclocal Options, Macro Search Path): Update.

1 files changed, 36 insertions, 38 deletions

diff --git a/aclocal.in b/aclocal.in
index 4b63c1afa..8b31bdca4 100644
--- a/aclocal.in
+++ b/aclocal.in
@@ -54,9 +54,11 @@ $perl_threads = 0;
 # Include paths for searching macros.  We search macros in this order:
 # user-supplied directories first, then the directory containing the
 # automake macros, and finally the system-wide directories for
-# third-party macro.  @user_includes can be augmented with -I.
-# @system_includes can be augmented with the `dirlist' file.  Also
-# --acdir will reset both @automake_includes and @system_includes.
+# third-party macros.
+# @user_includes can be augmented with -I.
+# @automake_includes can be reset with the `--automake-acdir' option.
+# @system_includes can be augmented with the `dirlist' file, and reset
+# with the `--system-acdir' option.
 my @user_includes = ();
 my @automake_includes = ("@datadir@/aclocal-$APIVERSION");
 my @system_includes = ('@datadir@/aclocal');
@@ -877,7 +879,8 @@ sub usage ($)
 Generate `aclocal.m4' by scanning `configure.ac' or `configure.in'
 
 Options:
-      --acdir=DIR           directory holding config files (for debugging)
+      --automake-acdir=DIR  directory holding automake-provided m4 files
+      --system-acdir=DIR    directory holding third-party system-wide files
       --diff[=COMMAND]      run COMMAND [diff -u] on M4 files that would be
                               changed (implies --install and --dry-run)
       --dry-run             pretend to, but do not actually update any file
@@ -886,7 +889,8 @@ Options:
   -I DIR                    add directory to search list for .m4 files
       --install             copy third-party files to the first -I directory
       --output=FILE         put output in FILE (default aclocal.m4)
-      --print-ac-dir        print name of directory holding m4 files, then exit
+      --print-ac-dir        print name of directory holding system-wide
+                              third-party m4 files, then exit
       --verbose             don't be silent
       --version             print version number, then exit
   -W, --warnings=CATEGORY   report the warnings falling in CATEGORY
@@ -923,6 +927,15 @@ EOF
   exit 0;
 }
 
+# Using --acdir overrides both the automake (versioned) directory and
+# the public (unversioned) system directory.  This usage is obsolete.
+sub handle_acdir_option ($$)
+{
+  msg 'obsolete', '', "`--acdir' is deprecated\n";
+  @system_includes = ($_[1]);
+  @automake_includes = ();
+}
+
 # Parse command line.
 sub parse_arguments ()
 {
@@ -931,12 +944,9 @@ sub parse_arguments ()
 
   my %cli_options =
     (
-     'acdir=s'		=> sub # Setting --acdir overrides both the
-                             { # automake (versioned) directory and the
-			       # public (unversioned) system directory.
-			       @automake_includes = ();
-			       @system_includes = ($_[1])
-			     },
+     'acdir=s'		=> \&handle_acdir_option,
+     'system-acdir=s'	=> sub { shift; @system_includes = @_; },
+     'automake-acdir=s'	=> sub { shift; @automake_includes = @_; },
      'diff:s'		=> \$diff_command,
      'dry-run'		=> \$dry_run,
      'force'		=> \$force_output,
@@ -1017,34 +1027,22 @@ sub parse_arguments ()
 	     . "\nfirst -I option, but no -I was supplied.");
     }
 
-  if (! -d $system_includes[0])
+  # Finally, adds any directory listed in the `dirlist' file.
+  if (open (DIRLIST, "$system_includes[0]/dirlist"))
     {
-      # By default $(datadir)/aclocal doesn't exist.  We don't want to
-      # get an error in the case where we are searching the default
-      # directory and it hasn't been created.  (We know
-      # @system_includes has its default value if @automake_includes
-      # is not empty, because --acdir is the only way to change this.)
-      @system_includes = () if @automake_includes;
-    }
-  else
-    {
-      # Finally, adds any directory listed in the `dirlist' file.
-      if (open (DIRLIST, "$system_includes[0]/dirlist"))
-	{
-	  while (<DIRLIST>)
-	    {
-	      # Ignore '#' lines.
-	      next if /^#/;
-	      # strip off newlines and end-of-line comments
-	      s/\s*\#.*$//;
-	      chomp;
-	      foreach my $dir (glob)
-		{
-		  push (@system_includes, $dir) if -d $dir;
-		}
-	    }
-	  close (DIRLIST);
-	}
+      while (<DIRLIST>)
+        {
+          # Ignore '#' lines.
+          next if /^#/;
+          # strip off newlines and end-of-line comments
+          s/\s*\#.*$//;
+          chomp;
+          foreach my $dir (glob)
+            {
+              push (@system_includes, $dir) if -d $dir;
+            }
+        }
+      close (DIRLIST);
     }
 }