[gtk/wip/chergert/glproto] add renderer to test utils

[Christian Hergert <chergert src gnome org>]

commit 1f5e3dde649c7f80658a9740a18d7348a0500b04
Author: Christian Hergert <chergert redhat com>
Date:   Sun Dec 20 09:26:56 2020 -0800

    add renderer to test utils

 gtk/gtktestutils.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gtk/gtktestutils.c b/gtk/gtktestutils.c
index 690931a153..64d4e5a4a1 100644
--- a/gtk/gtktestutils.c
+++ b/gtk/gtktestutils.c
@@ -41,6 +41,7 @@
 #define GTK_COMPILATION
 
 #include <gsk/gl/gskglrenderer.h>
+#include <gsk/next/gskglrenderer.h>
 
 #ifdef GDK_WINDOWING_BROADWAY
 #include <gsk/broadway/gskbroadwayrenderer.h>