Avoid gdk_display_get_name() on OS X

More in the comment.

src/socket.c

@@ -284,8 +284,15 @@ gint socket_init(gint argc, gchar **argv)
 	GdkDisplay *display = gdk_display_get_default();
 	gchar *p;
 
+	/* On OS X with quartz backend gdk_display_get_name() returns hostname
+	 * using [NSHost currentHost] (it could return more or less whatever string
+	 * as display name is a X11 specific thing). This call can lead to network
+	 * query and block for several seconds so better skip it. */
+#ifndef GDK_WINDOWING_QUARTZ
 	if (display != NULL)
 		display_name = g_strdup(gdk_display_get_name(display));
+#endif
+
 	if (display_name == NULL)
 		display_name = g_strdup("NODISPLAY");