Fixed X11 synchronization when message queue is

enabled and synchronize access to the 'waiting_for_input' variable

src/gui.c

@@ -87,7 +87,7 @@ gui_start()
 
     ++recursive;
 
-#if defined(FEAT_MESSAGEQUEUE) && defined(FEAT_GUI_X11)
+#if defined(FEAT_MESSAGEQUEUE) && defined(FEAT_X11)
     if (recursive <= 1) XInitThreads();
 #endif
 

src/main.c

@@ -171,7 +171,6 @@ main
 #ifdef STARTUPTIME
     int		i;
 #endif
-
     /*
      * Do any system-specific initialisations.  These can NOT use IObuff or
      * NameBuff.  Thus emsg2() cannot be called!

src/message_queue.c

@@ -16,11 +16,13 @@ typedef struct message_queue_T
 
 message_queue_T	    message_queue;
 
-int		    waiting_for_input;
 pthread_t	    input_thread;
 pthread_mutex_t	    input_mutex;
 pthread_cond_t	    input_cond;
 
+int		    waiting_for_input;
+pthread_mutex_t	    waiting_for_input_mutex;
+
 /* 
  * FIXME: Figure out the right way to deal with such errors by asking
  * on the list
@@ -69,8 +71,13 @@ input_wait()
     void
 input_notify()
 {
-    if (waiting_for_input)
+    lock(&waiting_for_input_mutex);
+    if (waiting_for_input) {
+	unlock(&waiting_for_input_mutex);
 	return;
+    }
+    unlock(&waiting_for_input_mutex);
+
 
     lock(&input_mutex);
 
@@ -93,13 +100,17 @@ vgetcs(arg)
 
     while (TRUE)
     {
+	lock(&waiting_for_input_mutex);
 	waiting_for_input = FALSE;
+	unlock(&waiting_for_input_mutex);
 
 	// Only try to read input when asked by the main thread
 	input_wait();
 
 	// Dont let the main thread call 'input_notify' or else it would block
+	lock(&waiting_for_input_mutex);
 	waiting_for_input = TRUE;
+	unlock(&waiting_for_input_mutex);
 
 	// Allocate space to hold input data
 	data = (input_data_T *)alloc(sizeof(input_data_T));
@@ -139,6 +150,8 @@ queue_init()
     if (pthread_cond_init(&message_queue.cond, NULL) != 0)
 	pthread_error("Failed to init the condition");
 
+    if (pthread_mutex_init(&waiting_for_input_mutex, NULL) != 0)
+	pthread_error("Failed to init the mutex");
 
     message_queue.head = NULL;
     message_queue.tail = NULL;