Add a sanity g_return_if_fail() check for the depths for the window and

Add a sanity g_return_if_fail() check for the depths for the window and

Tue May 14 15:40:49 2002  Owen Taylor  <otaylor@redhat.com>

        * gdk/x11/gdkwindow-{linux-fb,win32,x11.c} (gdk_window_set_back_pixmap):        Add a sanity g_return_if_fail() check for the depths
        for the window and pixmap. (#79191, Shivaram Upadhyayula)