[gnome-builder] add env var for experimental feature

[Christian Hergert <chergert src gnome org>]

commit e2e0460bcc0891eef8d4e38df81c906db36cdfc2
Author: Christian Hergert <christian hergert me>
Date:   Fri Mar 20 03:06:26 2015 -0700

    add env var for experimental feature

 libide/c/ide-c-language.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/libide/c/ide-c-language.c b/libide/c/ide-c-language.c
index e065e21..7557c99 100644
--- a/libide/c/ide-c-language.c
+++ b/libide/c/ide-c-language.c
@@ -52,9 +52,9 @@ ide_c_language_get_completion_providers (IdeLanguage *language)
   g_return_val_if_fail (IDE_IS_C_LANGUAGE (language), NULL);
 
   providers = g_list_append (providers, g_object_new (IDE_TYPE_C_FORMAT_PROVIDER, NULL));
-#if 0
-  providers = g_list_append (providers, g_object_new (IDE_TYPE_CLANG_COMPLETION_PROVIDER, NULL));
-#endif
+
+  if (g_getenv ("IDE_ENABLE_EXPERIMENTAL") != NULL)
+    providers = g_list_append (providers, g_object_new (IDE_TYPE_CLANG_COMPLETION_PROVIDER, NULL));
 
   return providers;
 }