Darwin: Dead code removal, Code cleanup, Added launcher

Imported changes from xorg-server-1.2-apple to make master more current wrt
file layout, build system changes, and dead code removal.

dix/main.c

@@ -256,10 +256,10 @@ main(int argc, char *argv[], char *envp[])
     PrinterInitGlobals();
 #endif
 
+#ifdef XQUARTZ
     /* Quartz support on Mac OS X requires that the Cocoa event loop be in
      * the main thread. This allows the X server main to be called again
      * from another thread. */
-#if defined(__DARWIN__) && defined(DARWIN_WITH_QUARTZ)
     DarwinHandleGUI(argc, argv, envp);
 #endif