[gnome-builder] context: add main thread check

[Christian Hergert <chergert src gnome org>]

commit 4ce62b95e1946f584e28e9c0e60a77dded2eb7b7
Author: Christian Hergert <chergert redhat com>
Date:   Fri Aug 3 14:22:19 2018 -0700

    context: add main thread check

 src/libide/ide-context.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/libide/ide-context.c b/src/libide/ide-context.c
index 5c1f50033..3bf0821fd 100644
--- a/src/libide/ide-context.c
+++ b/src/libide/ide-context.c
@@ -2913,6 +2913,7 @@ ide_context_cache_filename (IdeContext  *self,
 IdeVcsMonitor *
 ide_context_get_monitor (IdeContext *self)
 {
+  g_return_val_if_fail (IDE_IS_MAIN_THREAD (), NULL);
   g_return_val_if_fail (IDE_IS_CONTEXT (self), NULL);
 
   if (self->monitor == NULL)