[gtk] GdkGLContext: check for GL_KHR_debug for GL debug output

[Timm Bäder <baedert src gnome org>]

commit 2cbfb0e980348cb9cfd1184fea2eec2763aa1ca3
Author: Timm Bäder <mail baedert org>
Date:   Tue Dec 17 09:06:15 2019 +0100

    GdkGLContext: check for GL_KHR_debug for GL debug output
    
    This is available in GLES.

 gdk/gdkglcontext.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/gdk/gdkglcontext.c b/gdk/gdkglcontext.c
index 9f3ea5d938..ddf9cd3f95 100644
--- a/gdk/gdkglcontext.c
+++ b/gdk/gdkglcontext.c
@@ -955,7 +955,8 @@ gdk_gl_context_check_extensions (GdkGLContext *context)
   if (priv->use_es < 0)
     priv->use_es = !epoxy_is_desktop_gl ();
 
-  priv->has_debug_output = epoxy_has_gl_extension ("GL_ARB_debug_output");
+  priv->has_debug_output = epoxy_has_gl_extension ("GL_ARB_debug_output") ||
+                           epoxy_has_gl_extension ("GL_KHR_debug");
 
 #ifdef G_ENABLE_CONSISTENCY_CHECKS
   if (priv->has_debug_output)