Don't use undef value in Config::myconfig

(this is the same change as commit 754da6387aaed7d7ca907de8ac487143097ad5e3, but as applied)

diff --git a/configpm b/configpm
index fcf4e3d..8ea1420 100755 (executable)
--- a/configpm
+++ b/configpm
@@ -79,7 +79,8 @@ my $summary_expanded = 0;
 
 sub myconfig {
        return $summary if $summary_expanded;
-       $summary =~ s/\$(\w+)/$Config{$1}/ge;
+       $summary =~ s{\$(\w+)}
+                    { my $c = $Config{$1}; defined($c) ? $c : 'undef' }ge;
        $summary_expanded = 1;
        $summary;
 }