XQuartz: Use dispatch_async to handoff the FD

Signed-off-by: Jeremy Huddleston <jeremyhu@apple.com>

hw/xquartz/mach-startup/bundle-main.c

@@ -40,10 +40,15 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-#include <pthread.h>
 #include <stdbool.h>
 #include <signal.h>
 
+#ifdef HAVE_LIBDISPATCH
+#include <dispatch/dispatch.h>
+#else
+#include <pthread.h>
+#endif
+
 #include <sys/socket.h>
 #include <sys/un.h>
 
@@ -94,6 +99,7 @@ int server_main(int argc, char **argv, char **envp);
 static int execute(const char *command);
 static char *command_from_prefs(const char *key, const char *default_value);
 
+#ifndef HAVE_LIBDISPATCH
 /*** Pthread Magics ***/
 static pthread_t create_thread(void *(*func)(void *), void *arg) {
     pthread_attr_t attr;
@@ -107,6 +113,7 @@ static pthread_t create_thread(void *(*func)(void *), void *arg) {
 	
     return tid;
 }
+#endif
 
 /*** Mach-O IPC Stuffs ***/
 
@@ -199,8 +206,13 @@ typedef struct {
 /* This thread accepts an incoming connection and hands off the file
  * descriptor for the new connection to accept_fd_handoff()
  */
+#ifdef HAVE_LIBDISPATCH
+static void socket_handoff(socket_handoff_t *handoff_data) {
+#else
 static void *socket_handoff_thread(void *arg) {
     socket_handoff_t *handoff_data = (socket_handoff_t *)arg;
+#endif
+
     int launchd_fd = -1;
     int connected_fd;
 
@@ -229,7 +241,9 @@ static void *socket_handoff_thread(void *arg) {
     fprintf(stderr, "X11.app Handing off fd to server thread via DarwinListenOnOpenFD(%d)\n", launchd_fd);
     DarwinListenOnOpenFD(launchd_fd);
 
+#ifndef HAVE_LIBDISPATCH
     return NULL;
+#endif
 }
 
 static int create_socket(char *filename_out) {
@@ -298,8 +312,14 @@ kern_return_t do_request_fd_handoff_socket(mach_port_t port, string_t filename)
     }
 
     strlcpy(filename, handoff_data->filename, STRING_T_SIZE);
-    
+
+#ifdef HAVE_LIBDISPATCH
+    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0), ^{
+        socket_handoff(handoff_data);
+    });
+#else
     create_thread(socket_handoff_thread, handoff_data);
+#endif
     
 #ifdef DEBUG
     fprintf(stderr, "X11.app: Thread created for handoff.  Returning success to tell caller to connect and push the fd.\n");