[gnome-builder] subprocess: fix cast for return type

[Christian Hergert <chergert src gnome org>]

commit f39fb3fece6c000ff8ca9f2751f1f5b7a17e836b
Author: Christian Hergert <chergert redhat com>
Date:   Thu May 24 13:11:02 2018 -0700

    subprocess: fix cast for return type

 src/libide/subprocess/ide-breakout-subprocess.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/libide/subprocess/ide-breakout-subprocess.c b/src/libide/subprocess/ide-breakout-subprocess.c
index 09a456699..ebc868d67 100644
--- a/src/libide/subprocess/ide-breakout-subprocess.c
+++ b/src/libide/subprocess/ide-breakout-subprocess.c
@@ -1790,5 +1790,5 @@ _ide_breakout_subprocess_new (const gchar                 *cwd,
   if (!g_initable_init (G_INITABLE (ret), cancellable, error))
     return NULL;
 
-  return g_steal_pointer (&ret);
+  return IDE_SUBPROCESS (g_steal_pointer (&ret));
 }