XQuartz: pbproxy: Remove thread-main.m

it got accidently added and isn't used.
(cherry picked from commit cb6ffce68a2d10022fa92725d2d1837da4b3b89f)

hw/xquartz/pbproxy/thread-main.m

@@ -1,42 +0,0 @@
-/* app-main.m
- $Id: main.m,v 1.29 2007-04-07 20:39:03 jharper Exp $
- 
- Copyright (c) 2002, 2008 Apple Computer, Inc. All rights reserved. */
-
-#include "pbproxy.h"
-#import "x-selection.h"
-
-#include <pthread.h>
-#include <unistd.h> /*for getpid*/
-#include <Cocoa/Cocoa.h>
-
-static void signal_handler (int sig) {
-    switch(sig) {
-        case SIGHUP:
-            xpbproxy_prefs_reload = YES;
-            break;
-        default:
-            _exit(EXIT_SUCCESS);
-    }
-}
-
-int main (int argc, const char *argv[]) {
-#ifdef DEBUG
-    printf("pid: %u\n", getpid());
-#endif
-
-    xpbproxy_is_standalone = YES;
-    
-    if(!xpbproxy_init())
-        return EXIT_FAILURE;
-    
-    signal (SIGINT, signal_handler);
-    signal (SIGTERM, signal_handler);
-    signal (SIGHUP, signal_handler);
-    signal (SIGPIPE, SIG_IGN);
-
-    [NSApplication sharedApplication];
-    [NSApp run];
-    
-    return EXIT_SUCCESS;
-}