[gtk+] wayland: Don't "probe" for a Wayland compositor if started from compositor

[Rob Bradford <rbradford src gnome org>]

commit bff5b2ae3ee51e83564ead19f410be9ff0c00326
Author: Rob Bradford <rob linux intel com>
Date:   Fri Apr 12 18:39:20 2013 +0100

    wayland: Don't "probe" for a Wayland compositor if started from compositor
    
    In the case that the client is started directly by the compositor the
    WAYLAND_SOCKET environment variable is set containing the fd to use that was
    created by a socketpair.
    
    This environment variable is consumed by a call to wl_display_connect so a
    second call will not take advantage of it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=697673

 gdk/wayland/gdkdisplaymanager-wayland.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/gdk/wayland/gdkdisplaymanager-wayland.c b/gdk/wayland/gdkdisplaymanager-wayland.c
index 5d4e12b..0d73a78 100644
--- a/gdk/wayland/gdkdisplaymanager-wayland.c
+++ b/gdk/wayland/gdkdisplaymanager-wayland.c
@@ -59,6 +59,12 @@ gdk_wayland_display_manager_initable_init (GInitable     *initable,
 {
   struct wl_display *wl_display;
 
+  /* Set by the compositor when launching a special client - and it gets reset
+   * by wl_display_connect so we must avoid calling it twice
+   */
+  if (g_getenv ("WAYLAND_SOCKET"))
+    return TRUE;
+
   /* check that a connection to the default display is possible */
   wl_display = wl_display_connect (gdk_get_display_arg_name ());