[perl #47395] t/configure/115-auto-warnings.t assumes cc -Wall works.

[James Keenan via RT]

Patch posted by Jarkko Hietaniemi on parrot-porters.  I'll be looking at
this patch in conjunction with other fixes to this class and its tests.

kid51

--- config/auto/warnings.pm.dist        2008-01-08 05:51:42.000000000 +0200
+++ config/auto/warnings.pm     2008-01-08 06:01:23.000000000 +0200
@@ -132,17 +132,22 @@
     $verbose = $conf->options->get('verbose');
     print "\n" if $verbose;
 
-    # add on some extra warnings if requested
-    push @potential_warnings, @cage_warnings
-        if $conf->options->get('cage');
-
-    push @potential_warnings, '-Wlarger-than-4096'
-        if $conf->options->get('maintainer');
-
-    # now try out our warnings
-    for my $maybe_warning (@potential_warnings) {
-        $self->try_warning( $conf, $maybe_warning );
+    my $gcc = $conf->options->get('gccversion');
+
+    if (defined $gcc) {
+       # add on some extra warnings if requested
+       push @potential_warnings, @cage_warnings
+           if $conf->options->get('cage');
+
+       push @potential_warnings, '-Wlarger-than-4096'
+           if $conf->options->get('maintainer');
+
+       # now try out our warnings
+       for my $maybe_warning (@potential_warnings) {
+           $self->try_warning( $conf, $maybe_warning );
+       }
     }
+
     return 1;
 }