Index: lib/Parrot/Configure/Step/Methods.pm
===================================================================
--- lib/Parrot/Configure/Step/Methods.pm	(revision 27931)
+++ lib/Parrot/Configure/Step/Methods.pm	(working copy)
@@ -103,7 +103,7 @@
         my $ports_root = $conf->data->get( 'ports_base_dir' );
         my $ports_lib_dir = $conf->data->get( 'ports_lib_dir' );
         my $ports_include_dir = $conf->data->get( 'ports_include_dir' );
-        if ( -f qq{$ports_include_dir/$file} ) {
+        if ( $ports_include_dir && -f qq{$ports_include_dir/$file} ) {
             $conf->data->add( ' ', linkflags => "-L$ports_lib_dir" );
             $conf->data->add( ' ', ldflags   => "-L$ports_lib_dir" );
             $conf->data->add( ' ', ccflags   => "-I$ports_include_dir" );