Synch recent 3.4.2 changes to main trunk

This is merely a synchronization of recent changes for the
Macintosh Carbon port, which were committed to the 3.4.2
branch, to the main trunk.

include/mttypriv.h

@@ -15,9 +15,11 @@
 #include "mactty.h"
 # endif
 
-#include <QDOffscreen.h>
-#include <Gestalt.h>
-#include <Errors.h>
+#if !TARGET_API_MAC_CARBON
+# include <QDOffscreen.h>
+# include <Gestalt.h>
+# include <Errors.h>
+#endif
 
 #define TA_TO_RGB(ta,rgb) (((rgb).red=(((ta)>>16)&0xff)*257),((rgb).green=(((ta)>>8)&0xff)*257),\
 	((rgb).blue=((ta)&0xff)*257)),rgb