[gtk+] GtkStyleSet: Prevent from possible underflow.

[Carlos Garnacho <carlosg src gnome org>]

commit c88e3bfc0c3e89bc09d4b3604fe62e4a3d11b2a5
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Oct 26 00:16:22 2010 +0200

    GtkStyleSet: Prevent from possible underflow.

 gtk/gtkstyleset.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkstyleset.c b/gtk/gtkstyleset.c
index 94a4136..6009329 100644
--- a/gtk/gtkstyleset.c
+++ b/gtk/gtkstyleset.c
@@ -309,7 +309,12 @@ compare_property (gconstpointer p1,
   PropertyNode *key = (PropertyNode *) p1;
   PropertyNode *node = (PropertyNode *) p2;
 
-  return (int) key->property_quark - node->property_quark;
+  if (key->property_quark > node->property_quark)
+    return 1;
+  else if (key->property_quark < node->property_quark)
+    return -1;
+
+  return 0;
 }
 
 static PropertyNode *