--- a/lib-src/config.values.sh	Mon Aug 13 11:30:00 2007 +0200
+++ b/lib-src/config.values.sh	Mon Aug 13 11:30:53 2007 +0200
@@ -1,4 +1,7 @@
-#! /bin/sh
+: #-*- Perl -*-
+eval 'exec perl -w -S $0 ${1+"$@"}' # Portability kludge
+    if 0;
+
 # config.values.sh --- create config.values.in from ../configure
 
 # Author:	Martin Buchholz
@@ -35,17 +38,27 @@
 ## by an XEmacs Maintainer (consider yourself so blessed, if you are
 ## actually reading this commentary).
 ##
-if test ! -r ./configure; then
-  cd ..
-  if test ! -r ./configure; then
-    echo "Can't find configure!";
-    exit 1;
-  fi
-fi
+
+if (! -r "./configure") {
+  chdir ".." or die "Can't chdir: $!";
+  if (! -r "./configure") {
+    die "Can't find configure!";
+  }
+}
 
-exec < ./configure > "lib-src/config.values.in"
-cat <<\EOF
-;;; Do not edit this file!
+sub FileContents {
+  local $/ = undef; # Slurp mode
+  open (FILE, "< $_[0]") or die "$_[0]: $!";
+  my $contents = <FILE>;
+  close FILE or die "$_[0]: $!";
+  return $contents;
+}
+
+my $configure_contents = FileContents "./configure";
+my $cvi_contents = FileContents "lib-src/config.values.in";
+
+my $new_cvi_contents =
+";;; Do not edit this file!
 ;;; This file was automatically generated, by the config.values.sh script,
 ;;; from configure, which was itself automatically generated from configure.in.
 ;;;
@@ -62,15 +75,27 @@
 ;;; Variables defined in configure by AC_SUBST follow:
 ;;; (These are used in Makefiles)
 
-EOF
-sed -n '/^s%@\([A-Za-z_][A-Za-z_]*\)@%\$\1%g$/ {
-  s/^s%@\([A-Za-z_][A-Za-z_]*\)@%\$\1%g$/\1 "@\1@"/
-  p
-}' | \
-sort -u
-cat <<\EOF
+";
 
+my %done;
+for my $var (sort { $a cmp $b }
+	     $configure_contents =~
+	     /^s\%\@([A-Za-z0-9_]+)\@\%\$[A-Za-z0-9_]+\%g/mg) {
+  $new_cvi_contents .= "$var \"\@$var\@\"\n" unless exists $done{$var};
+  $done{$var} = 1;
+}
+
+$new_cvi_contents .= "
 ;;; Variables defined in configure by AC_DEFINE and AC_DEFINE_UNQUOTED follow:
 ;;; (These are used in C code)
 
-EOF
+";
+
+if ($cvi_contents ne $new_cvi_contents) {
+  unlink "lib-src/config.values.in";
+  open (CVI, "> lib-src/config.values.in")
+    or die "lib-src/config.values.in: $!";
+  print CVI $new_cvi_contents;
+  close CVI
+    or die "lib-src/config.values.in: $!";
+}