Add Perl test to the configuration.

6 files changed, 519 insertions, 50 deletions

diff --git a/ChangeLog b/ChangeLog
index 87891af0..1972bf7a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,21 @@
+2013-04-15  Bernd Warken  <groff-bernd.warken-72@web.de>
+
+	Add Perl test to configuration.  During the run of `configure' the
+	program is broken with error when there is no `Perl' or the `perl'
+	program is too old.
+
+	* m4/groff.m4: Add macro `GROFF_PERL' that tests the availability
+	of the `perl' program and tests wether this has a version of at
+	most `v5.6.1'.  Define variables $PERL and $PERLPATH for the full
+	name of the `perl' program and $PERLVERSION as the lest version.
+
+	* configure.ac: Add information of the macro `GROFF_PERL'.
+
+	* Makefile.in: Add definitions of the macro variables and their
+	`@...@' counterparts.
+
+	Run `autoreconf -I m4'.
+
 2013-04-13  Keith Marshall  <keithmarshall@users.sourceforge.net>
 
 	Avoid consideration of autotool cache for CVS inclusion.
diff --git a/Makefile.in b/Makefile.in
index f9942fa8..cba07f7f 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -429,7 +429,9 @@ ETAGSFLAGS=
 # Flag that tells etags to assume C++.
 ETAGSCCFLAG=-C
 # Full path to perl.
+PERL=@PERL@
 PERLPATH=@PERLPATH@
+PERLVERSION=@PERLVERSION@
 # Sed command with which to edit sh scripts.
 SH_SCRIPT_SED_CMD=@SH_SCRIPT_SED_CMD@
 # Sed script to deal with OS dependencies in sh scripts.
@@ -483,7 +485,7 @@ MDEFINES=\
   "OTHERDEVDIRS=$(OTHERDEVDIRS)" \
   "PAGE=$(PAGE)" \
   "GHOSTSCRIPT=$(GHOSTSCRIPT)" \
-  "PERLPATH=$(PERLPATH)" \
+  "PERLPATH=$(PERL)" \
   "PSPRINT=$(PSPRINT)" \
   "PURIFY=$(PURIFY)" \
   "PURIFYCCFLAGS=$(PURIFYCCFLAGS)" \
@@ -635,7 +637,7 @@ OTHERDIRS=\
   font/devpdf \
   contrib/mom \
   contrib/gdiffmk
-  
+
 # OTHERDIRS is handled specially in the `$(TARGETS)' rule to avoid
 # dependency problems with parallel builds.
 ALLDIRS=\
diff --git a/aclocal.m4 b/aclocal.m4
index 022a45bc..78070fb8 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1,7 +1,8 @@
-# generated automatically by aclocal 1.12.5 -*- Autoconf -*-
-
-# Copyright (C) 1996-2012 Free Software Foundation, Inc.
+# generated automatically by aclocal 1.11.6 -*- Autoconf -*-
 
+# Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
+# 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation,
+# Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
@@ -11,6 +12,251 @@
 # even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 # PARTICULAR PURPOSE.
 
+# ===========================================================================
+#    http://www.gnu.org/software/autoconf-archive/ax_compare_version.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_COMPARE_VERSION(VERSION_A, OP, VERSION_B, [ACTION-IF-TRUE], [ACTION-IF-FALSE])
+#
+# DESCRIPTION
+#
+#   This macro compares two version strings. Due to the various number of
+#   minor-version numbers that can exist, and the fact that string
+#   comparisons are not compatible with numeric comparisons, this is not
+#   necessarily trivial to do in a autoconf script. This macro makes doing
+#   these comparisons easy.
+#
+#   The six basic comparisons are available, as well as checking equality
+#   limited to a certain number of minor-version levels.
+#
+#   The operator OP determines what type of comparison to do, and can be one
+#   of:
+#
+#    eq  - equal (test A == B)
+#    ne  - not equal (test A != B)
+#    le  - less than or equal (test A <= B)
+#    ge  - greater than or equal (test A >= B)
+#    lt  - less than (test A < B)
+#    gt  - greater than (test A > B)
+#
+#   Additionally, the eq and ne operator can have a number after it to limit
+#   the test to that number of minor versions.
+#
+#    eq0 - equal up to the length of the shorter version
+#    ne0 - not equal up to the length of the shorter version
+#    eqN - equal up to N sub-version levels
+#    neN - not equal up to N sub-version levels
+#
+#   When the condition is true, shell commands ACTION-IF-TRUE are run,
+#   otherwise shell commands ACTION-IF-FALSE are run. The environment
+#   variable 'ax_compare_version' is always set to either 'true' or 'false'
+#   as well.
+#
+#   Examples:
+#
+#     AX_COMPARE_VERSION([3.15.7],[lt],[3.15.8])
+#     AX_COMPARE_VERSION([3.15],[lt],[3.15.8])
+#
+#   would both be true.
+#
+#     AX_COMPARE_VERSION([3.15.7],[eq],[3.15.8])
+#     AX_COMPARE_VERSION([3.15],[gt],[3.15.8])
+#
+#   would both be false.
+#
+#     AX_COMPARE_VERSION([3.15.7],[eq2],[3.15.8])
+#
+#   would be true because it is only comparing two minor versions.
+#
+#     AX_COMPARE_VERSION([3.15.7],[eq0],[3.15])
+#
+#   would be true because it is only comparing the lesser number of minor
+#   versions of the two values.
+#
+#   Note: The characters that separate the version numbers do not matter. An
+#   empty string is the same as version 0. OP is evaluated by autoconf, not
+#   configure, so must be a string, not a variable.
+#
+#   The author would like to acknowledge Guido Draheim whose advice about
+#   the m4_case and m4_ifvaln functions make this macro only include the
+#   portions necessary to perform the specific comparison specified by the
+#   OP argument in the final configure script.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Tim Toolan <toolan@ele.uri.edu>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 11
+
+dnl #########################################################################
+AC_DEFUN([AX_COMPARE_VERSION], [
+  AC_REQUIRE([AC_PROG_AWK])
+
+  # Used to indicate true or false condition
+  ax_compare_version=false
+
+  # Convert the two version strings to be compared into a format that
+  # allows a simple string comparison.  The end result is that a version
+  # string of the form 1.12.5-r617 will be converted to the form
+  # 0001001200050617.  In other words, each number is zero padded to four
+  # digits, and non digits are removed.
+  AS_VAR_PUSHDEF([A],[ax_compare_version_A])
+  A=`echo "$1" | sed -e 's/\([[0-9]]*\)/Z\1Z/g' \
+                     -e 's/Z\([[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/[[^0-9]]//g'`
+
+  AS_VAR_PUSHDEF([B],[ax_compare_version_B])
+  B=`echo "$3" | sed -e 's/\([[0-9]]*\)/Z\1Z/g' \
+                     -e 's/Z\([[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/[[^0-9]]//g'`
+
+  dnl # In the case of le, ge, lt, and gt, the strings are sorted as necessary
+  dnl # then the first line is used to determine if the condition is true.
+  dnl # The sed right after the echo is to remove any indented white space.
+  m4_case(m4_tolower($2),
+  [lt],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort -r | sed "s/x${A}/false/;s/x${B}/true/;1q"`
+  ],
+  [gt],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort | sed "s/x${A}/false/;s/x${B}/true/;1q"`
+  ],
+  [le],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort | sed "s/x${A}/true/;s/x${B}/false/;1q"`
+  ],
+  [ge],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort -r | sed "s/x${A}/true/;s/x${B}/false/;1q"`
+  ],[
+    dnl Split the operator from the subversion count if present.
+    m4_bmatch(m4_substr($2,2),
+    [0],[
+      # A count of zero means use the length of the shorter version.
+      # Determine the number of characters in A and B.
+      ax_compare_version_len_A=`echo "$A" | $AWK '{print(length)}'`
+      ax_compare_version_len_B=`echo "$B" | $AWK '{print(length)}'`
+
+      # Set A to no more than B's length and B to no more than A's length.
+      A=`echo "$A" | sed "s/\(.\{$ax_compare_version_len_B\}\).*/\1/"`
+      B=`echo "$B" | sed "s/\(.\{$ax_compare_version_len_A\}\).*/\1/"`
+    ],
+    [[0-9]+],[
+      # A count greater than zero means use only that many subversions
+      A=`echo "$A" | sed "s/\(\([[0-9]]\{4\}\)\{m4_substr($2,2)\}\).*/\1/"`
+      B=`echo "$B" | sed "s/\(\([[0-9]]\{4\}\)\{m4_substr($2,2)\}\).*/\1/"`
+    ],
+    [.+],[
+      AC_WARNING(
+        [illegal OP numeric parameter: $2])
+    ],[])
+
+    # Pad zeros at end of numbers to make same length.
+    ax_compare_version_tmp_A="$A`echo $B | sed 's/./0/g'`"
+    B="$B`echo $A | sed 's/./0/g'`"
+    A="$ax_compare_version_tmp_A"
+
+    # Check for equality or inequality as necessary.
+    m4_case(m4_tolower(m4_substr($2,0,2)),
+    [eq],[
+      test "x$A" = "x$B" && ax_compare_version=true
+    ],
+    [ne],[
+      test "x$A" != "x$B" && ax_compare_version=true
+    ],[
+      AC_WARNING([illegal OP parameter: $2])
+    ])
+  ])
+
+  AS_VAR_POPDEF([A])dnl
+  AS_VAR_POPDEF([B])dnl
+
+  dnl # Execute ACTION-IF-TRUE / ACTION-IF-FALSE.
+  if test "$ax_compare_version" = "true" ; then
+    m4_ifvaln([$4],[$4],[:])dnl
+    m4_ifvaln([$5],[else $5])dnl
+  fi
+]) dnl AX_COMPARE_VERSION
+
+# ===========================================================================
+#   http://www.gnu.org/software/autoconf-archive/ax_prog_perl_version.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PROG_PERL_VERSION([VERSION],[ACTION-IF-TRUE],[ACTION-IF-FALSE])
+#
+# DESCRIPTION
+#
+#   Makes sure that perl supports the version indicated. If true the shell
+#   commands in ACTION-IF-TRUE are executed. If not the shell commands in
+#   ACTION-IF-FALSE are run. Note if $PERL is not set (for example by
+#   running AC_CHECK_PROG or AC_PATH_PROG) the macro will fail.
+#
+#   Example:
+#
+#     AC_PATH_PROG([PERL],[perl])
+#     AX_PROG_PERL_VERSION([5.8.0],[ ... ],[ ... ])
+#
+#   This will check to make sure that the perl you have supports at least
+#   version 5.8.0.
+#
+#   NOTE: This macro uses the $PERL variable to perform the check.
+#   AX_WITH_PERL can be used to set that variable prior to running this
+#   macro. The $PERL_VERSION variable will be valorized with the detected
+#   version.
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Francesco Salvestrini <salvestrini@users.sourceforge.net>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 11
+
+AC_DEFUN([AX_PROG_PERL_VERSION],[
+    AC_REQUIRE([AC_PROG_SED])
+    AC_REQUIRE([AC_PROG_GREP])
+
+    AS_IF([test -n "$PERL"],[
+        ax_perl_version="$1"
+
+        AC_MSG_CHECKING([for perl version])
+        changequote(<<,>>)
+        perl_version=`$PERL --version 2>&1 | $GREP "This is perl" | $SED -e 's/.* v\([0-9]*\.[0-9]*\.[0-9]*\) .*/\1/'`
+        changequote([,])
+        AC_MSG_RESULT($perl_version)
+
+	AC_SUBST([PERL_VERSION],[$perl_version])
+
+        AX_COMPARE_VERSION([$ax_perl_version],[le],[$perl_version],[
+	    :
+            $2
+        ],[
+	    :
+            $3
+        ])
+    ],[
+        AC_MSG_WARN([could not find the perl interpreter])
+        $3
+    ])
+])
+
 m4_include([m4/codeset.m4])
 m4_include([m4/fcntl-o.m4])
 m4_include([m4/glibc21.m4])
diff --git a/configure b/configure
index ebcf435c..9bd5d83c 100755
--- a/configure
+++ b/configure
@@ -630,7 +630,6 @@ pnmtops_nosetpage
 make_install_pdfdoc
 make_pdfdoc
 ac_ct_AWK
-AWK
 ALT_AWK_PROGS
 make_install_html
 make_html
@@ -672,12 +671,15 @@ INSTALL_INFO
 RANLIB
 MAKEINFO
 YACC
-PERLPATH
 DVIPRINT
 PSPRINT
 LPQ
 LP
 LPR
+AWK
+PERL_VERSION
+SED
+PERL
 groffer_dir
 appresdir
 XLIBDIRS
@@ -5533,6 +5535,234 @@ glilypond_dir=$libdir/groff/glilypond
 
 grog_dir=$libdir/groff/grog
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for a sed that does not truncate output" >&5
+$as_echo_n "checking for a sed that does not truncate output... " >&6; }
+if ${ac_cv_path_SED+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+            ac_script=s/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb/
+     for ac_i in 1 2 3 4 5 6 7; do
+       ac_script="$ac_script$as_nl$ac_script"
+     done
+     echo "$ac_script" 2>/dev/null | sed 99q >conftest.sed
+     { ac_script=; unset ac_script;}
+     if test -z "$SED"; then
+  ac_path_SED_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in sed gsed; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_SED="$as_dir/$ac_prog$ac_exec_ext"
+      as_fn_executable_p "$ac_path_SED" || continue
+# Check for GNU ac_path_SED and select it if it is found.
+  # Check for GNU $ac_path_SED
+case `"$ac_path_SED" --version 2>&1` in
+*GNU*)
+  ac_cv_path_SED="$ac_path_SED" ac_path_SED_found=:;;
+*)
+  ac_count=0
+  $as_echo_n 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    $as_echo '' >> "conftest.nl"
+    "$ac_path_SED" -f conftest.sed < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_SED_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_SED="$ac_path_SED"
+      ac_path_SED_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_SED_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_SED"; then
+    as_fn_error $? "no acceptable sed could be found in \$PATH" "$LINENO" 5
+  fi
+else
+  ac_cv_path_SED=$SED
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_SED" >&5
+$as_echo "$ac_cv_path_SED" >&6; }
+ SED="$ac_cv_path_SED"
+  rm -f conftest.sed
+
+for ac_prog in gawk mawk nawk awk
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_AWK+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$AWK"; then
+  ac_cv_prog_AWK="$AWK" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_AWK="$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+AWK=$ac_cv_prog_AWK
+if test -n "$AWK"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $AWK" >&5
+$as_echo "$AWK" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  test -n "$AWK" && break
+done
+
+PERLVERSION=v5.6.1
+	# Extract the first word of "perl", so it can be a program name with args.
+set dummy perl; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_path_PERL+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  case $PERL in
+  [\\/]* | ?:[\\/]*)
+  ac_cv_path_PERL="$PERL" # Let the user override the test with a path.
+  ;;
+  *)
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_path_PERL="$as_dir/$ac_word$ac_exec_ext"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+  test -z "$ac_cv_path_PERL" && ac_cv_path_PERL="no"
+  ;;
+esac
+fi
+PERL=$ac_cv_path_PERL
+if test -n "$PERL"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PERL" >&5
+$as_echo "$PERL" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+	if test "$PERL" = "no"; then
+	  as_fn_error 1 "perl binary not found" "$LINENO" 5
+	fi
+
+
+
+
+    if test -n "$PERL"; then :
+
+        ax_perl_version="$PERLVERSION"
+
+        { $as_echo "$as_me:${as_lineno-$LINENO}: checking for perl version" >&5
+$as_echo_n "checking for perl version... " >&6; }
+
+        perl_version=`$PERL --version 2>&1 | $GREP "This is perl" | $SED -e 's/.* v\([0-9]*\.[0-9]*\.[0-9]*\) .*/\1/'`
+
+        { $as_echo "$as_me:${as_lineno-$LINENO}: result: $perl_version" >&5
+$as_echo "$perl_version" >&6; }
+
+	PERL_VERSION=$perl_version
+
+
+
+
+
+  # Used to indicate true or false condition
+  ax_compare_version=false
+
+  # Convert the two version strings to be compared into a format that
+  # allows a simple string comparison.  The end result is that a version
+  # string of the form 1.12.5-r617 will be converted to the form
+  # 0001001200050617.  In other words, each number is zero padded to four
+  # digits, and non digits are removed.
+
+  ax_compare_version_A=`echo "$ax_perl_version" | sed -e 's/\([0-9]*\)/Z\1Z/g' \
+                     -e 's/Z\([0-9]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([0-9][0-9]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([0-9][0-9][0-9]\)Z/Z0\1Z/g' \
+                     -e 's/[^0-9]//g'`
+
+
+  ax_compare_version_B=`echo "$perl_version" | sed -e 's/\([0-9]*\)/Z\1Z/g' \
+                     -e 's/Z\([0-9]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([0-9][0-9]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([0-9][0-9][0-9]\)Z/Z0\1Z/g' \
+                     -e 's/[^0-9]//g'`
+
+
+    ax_compare_version=`echo "x$ax_compare_version_A
+x$ax_compare_version_B" | sed 's/^ *//' | sort | sed "s/x${ax_compare_version_A}/true/;s/x${ax_compare_version_B}/false/;1q"`
+
+
+
+    if test "$ax_compare_version" = "true" ; then
+
+	    :
+            PERLPATH=$PERL
+
+    else
+	    :
+            \
+          as_fn_error 1 "perl version is too old" "$LINENO" 5
+
+  fi
+
+
+else
+
+        { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: could not find the perl interpreter" >&5
+$as_echo "$as_me: WARNING: could not find the perl interpreter" >&2;}
+        \
+          as_fn_error 1 "perl version is too old" "$LINENO" 5
+
+fi
+
 if test -z "$PSPRINT"; then
      for ac_prog in lpr
 do
@@ -5758,47 +5988,6 @@ $as_echo "$ac_cv_path_EGREP" >&6; }
  EGREP="$ac_cv_path_EGREP"
 
 
-# Extract the first word of "perl", so it can be a program name with args.
-set dummy perl; ac_word=$2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
-$as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_path_PERLPATH+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  case $PERLPATH in
-  [\\/]* | ?:[\\/]*)
-  ac_cv_path_PERLPATH="$PERLPATH" # Let the user override the test with a path.
-  ;;
-  *)
-  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-for as_dir in $PATH
-do
-  IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    for ac_exec_ext in '' $ac_executable_extensions; do
-  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    ac_cv_path_PERLPATH="$as_dir/$ac_word$ac_exec_ext"
-    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
-    break 2
-  fi
-done
-  done
-IFS=$as_save_IFS
-
-  test -z "$ac_cv_path_PERLPATH" && ac_cv_path_PERLPATH="/usr/bin/perl"
-  ;;
-esac
-fi
-PERLPATH=$ac_cv_path_PERLPATH
-if test -n "$PERLPATH"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PERLPATH" >&5
-$as_echo "$PERLPATH" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-fi
-
-
 for ac_prog in byacc 'bison -y'
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
@@ -11255,6 +11444,7 @@ gives unlimited permission to copy, distribute and modify it."
 ac_pwd='$ac_pwd'
 srcdir='$srcdir'
 INSTALL='$INSTALL'
+AWK='$AWK'
 test -n "\$AWK" || AWK=awk
 _ACEOF
 
diff --git a/configure.ac b/configure.ac
index a6fa7041..5ee82cc9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -64,9 +64,9 @@ GROFF_GROFFERDIR_OPTION
 GROFF_GROFFERDIR_DEFAULT
 GROFF_GLILYPONDDIR_DEFAULT
 GROFF_GROGDIR_DEFAULT
+GROFF_PERL
 GROFF_PRINT
 AC_PROG_EGREP
-AC_PATH_PROG([PERLPATH], [perl], [/usr/bin/perl])
 GROFF_PROG_YACC
 GROFF_MAKEINFO
 AC_PROG_RANLIB
diff --git a/m4/groff.m4 b/m4/groff.m4
index cf105b2f..6f751ffd 100644
--- a/m4/groff.m4
+++ b/m4/groff.m4
@@ -2,7 +2,7 @@
 # Copyright (C) 1989-1995, 2001-2007, 2009, 2011, 2013
 #   Free Software Foundation, Inc.
 #
-# Last update: 28 Mar 2013
+# Last update: 14 Apr 2013
 #
 # This file is part of groff.
 #
@@ -58,6 +58,19 @@ AC_DEFUN([GROFF_PRINT],
 AC_DEFUN([GROFF_PROG_YACC],
   [AC_CHECK_PROGS([YACC], [byacc 'bison -y'], [yacc])])
 
+
+# We need Perl 5.6.1 or newer.
+
+AC_DEFUN([GROFF_PERL],
+	[PERLVERSION=v5.6.1
+	AC_PATH_PROG([PERL], [perl], [no])
+	if test "$PERL" = "no"; then
+	  AC_MSG_ERROR([perl binary not found], 1)
+	fi
+        AX_PROG_PERL_VERSION([$PERLVERSION], PERLPATH=$PERL, \
+          AC_MSG_ERROR([perl version is too old], 1))])
+
+
 # We need makeinfo 4.8 or newer.
 
 AC_DEFUN([GROFF_MAKEINFO],