[gnome-builder/gnome-builder-3-18] tags: allow NULL cancellable

[Christian Hergert <chergert src gnome org>]

commit a0c46cc05aa249ed738a46a3cfba22d877bc7483
Author: Christian Hergert <chergert redhat com>
Date:   Mon Oct 12 22:18:24 2015 -0400

    tags: allow NULL cancellable

 libide/ide-tags-builder.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libide/ide-tags-builder.c b/libide/ide-tags-builder.c
index 98a5d62..d6d47a3 100644
--- a/libide/ide-tags-builder.c
+++ b/libide/ide-tags-builder.c
@@ -31,7 +31,7 @@ ide_tags_builder_build_async (IdeTagsBuilder      *self,
 {
   g_return_if_fail (IDE_IS_TAGS_BUILDER (self));
   g_return_if_fail (!directory_or_file || G_IS_FILE (directory_or_file));
-  g_return_if_fail (G_IS_CANCELLABLE (cancellable));
+  g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
 
   IDE_TAGS_BUILDER_GET_IFACE (self)->build_async (self, directory_or_file, recursive, cancellable, callback, 
user_data);
 }