[gtk/wip/chergert/glproto] skip if no texture to render

[Christian Hergert <chergert src gnome org>]

commit b4bc1fcd83c4cd38a6ec0d1bdd09c335ea28df73
Author: Christian Hergert <chergert redhat com>
Date:   Tue Jan 19 14:52:45 2021 -0800

    skip if no texture to render

 gsk/next/gskglglyphlibrary.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gsk/next/gskglglyphlibrary.c b/gsk/next/gskglglyphlibrary.c
index 3b633bafdc..f527948d16 100644
--- a/gsk/next/gskglglyphlibrary.c
+++ b/gsk/next/gskglglyphlibrary.c
@@ -305,5 +305,5 @@ gsk_gl_glyph_library_add (GskGLGlyphLibrary      *self,
 
   *out_value = value;
 
-  return TRUE;
+  return GSK_GL_TEXTURE_ATLAS_ENTRY_TEXTURE (value) != 0;
 }