Fixed generated C files with wrong GSL version numbers.

Build.PL

@@ -126,14 +126,14 @@ my $builder = GSLBuilder->new(
         'Test::Class'     =>    '0.12',
     },
     requires => {
-        'PkgConfig'       => '0.07520',
+        'PkgConfig'       => '0.07720',
         'Scalar::Util'    => 0,
         version           => '0.77',
         perl              => '5.8.0',
     },
     sign                  => 0,
     configure_requires => {
-        'PkgConfig'       => '0.07520',
+        'PkgConfig'       => '0.07720',
         'Module::Build'   => '0.38',
     },
     swig_source           => [
@@ -276,7 +276,7 @@ sub check_gsl_version_pkgconfig {
 
 	return {
 		gsl_version => $gsl_version,
-		gsl_prefix  => undef,
+		gsl_prefix  => $gsl_pkgcfg->get_var("prefix"),
 		gsl_libs    => join (" ", $gsl_pkgcfg->get_ldflags),
 		gsl_cflags  => join (" ", $gsl_pkgcfg->get_cflags),
 	};

Changes

@@ -1,5 +1,6 @@
 =head1 Math::GSL Changes
 
+    - Fixed generated C files with wrong GSL version numbers.
     - Refactored Build.PL in order to use either gsl-config or PkgConfig.
     - Change Build.PL to return 0 when GSL library not found.
     - Use PkgConfig instead of ExtUtils::PkgConfig.

inc/GSLBuilder.pm

@@ -159,7 +159,7 @@ sub process_swig {
 
     # don't bother with swig if this is a CPAN release
     $self->compile_swig($main_swig_file, $c_file, $ver)
-        unless($self->up_to_date([$main_swig_file, @deps], $c_file));
+        unless $self->up_to_date([$main_swig_file, @deps], $c_file);
 }
 
 sub swig_binary_name {
@@ -209,6 +209,23 @@ sub compile_swig {
 	    or die "error : $! while building ( @swig_flags ) $c_file in $gsldir from '$file'";
     move($from, "$from.$ver");
 
+    {
+      ## updates the version number. 
+      ## all files are being processed right now.
+      ## later versions might use a fixed list of candidate files.
+      undef $/;
+      open my $in, "<", $c_file or die "Can't open file $c_file: $!";
+      my $contents = <$in>;
+      close $in;
+
+      $contents =~ s{("GSL_VERSION", TRUE \| 0x2 \| GV_ADDMULTI\);[\s\n]*sv_setsv\(sv, SWIG_FromCharPtr\(")\d\.\d+}
+                    {$1$ver};
+
+      open my $out, ">", $c_file or die "Can't overwrite file $c_file: $!";
+      print $out $contents;
+      close $out;
+    }
+
     if ($p->{current_version} eq $ver) {
         print "Copying from: $from.$ver, to: $to; it makes the CPAN indexer happy.\n";
         copy("$from.$ver", $to);