Added return NULL; for __WXCOCOA__

FIXME: The platform specific stuff is a real mess


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@21254 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/gdicmn.cpp

@@ -357,6 +357,9 @@ wxColour *wxColourDatabase::FindColour(const wxString& colour)
 #ifdef __WXMAC__
   return NULL;
 #endif
+#ifdef __WXCOCOA__
+  return NULL;
+#endif
 #ifdef __WXSTUBS__
   return NULL;
 #endif