[glib] gmain: Document that set_ready_time() is safe on destroyed GSources

[Philip Withnall <pwithnall src gnome org>]

commit 32aae79db558ec6d18577a605254b5ebf9800960
Author: Philip Withnall <withnall endlessm com>
Date:   Thu Mar 23 15:07:49 2017 +0000

    gmain: Document that set_ready_time() is safe on destroyed GSources
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=778049

 glib/gmain.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/glib/gmain.c b/glib/gmain.c
index 7d23d7c..a503431 100644
--- a/glib/gmain.c
+++ b/glib/gmain.c
@@ -1809,6 +1809,9 @@ g_source_get_priority (GSource *source)
  * for both sources is reached during the same main context iteration
  * then the order of dispatch is undefined.
  *
+ * It is a no-op to call this function on a #GSource which has already been
+ * destroyed with g_source_destroy().
+ *
  * This API is only intended to be used by implementations of #GSource.
  * Do not call this API on a #GSource that you did not create.
  *