[gnome-builder] clang: add missing cast.

[Sébastien Lafargue <slafargue src gnome org>]

commit d083cdb87e1ccdb3b337dc88834cb1f5d61ef43b
Author: Sebastien Lafargue <slafargue gnome org>
Date:   Sun Sep 27 19:57:42 2015 +0200

    clang: add missing cast.

 plugins/clang/ide-clang-translation-unit.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/plugins/clang/ide-clang-translation-unit.c b/plugins/clang/ide-clang-translation-unit.c
index 40fa81c..0d77893 100644
--- a/plugins/clang/ide-clang-translation-unit.c
+++ b/plugins/clang/ide-clang-translation-unit.c
@@ -704,7 +704,7 @@ ide_clang_translation_unit_code_complete_worker (GTask        *task,
     {
       GtkSourceCompletionProposal *proposal;
 
-      proposal = ide_clang_completion_item_new (refptr, i);
+      proposal = GTK_SOURCE_COMPLETION_PROPOSAL (ide_clang_completion_item_new (refptr, i));
       g_ptr_array_add (ar, proposal);
     }