Remove few more errors in mac scons build.

webkit/glue/event_conversion.cc

Index: webkit/glue/event_conversion.cc
===================================================================
--- webkit/glue/event_conversion.cc	(revision 6978)
+++ webkit/glue/event_conversion.cc	(working copy)
@@ -151,6 +151,8 @@
   return String(&c, 1);
 }
 
+#if !defined(OS_MACOSX)
+// This function is not used on Mac OS X, and gcc complains.
 static String GetKeyIdentifierForWindowsKeyCode(unsigned short keyCode) {
   switch (keyCode) {
     case VKEY_MENU:
@@ -253,6 +255,7 @@
       return String::format("U+%04X", toupper(keyCode));
   }
 }
+#endif  // !defined(OS_MACOSX)
 
 MakePlatformKeyboardEvent::MakePlatformKeyboardEvent(const WebKeyboardEvent& e)
   {