[gtk+] gl renderer: Sprinkle some const around

[Timm Bäder <baedert src gnome org>]

commit b9a05be2dab5c49996d176d1aa36c3883082b86d
Author: Timm Bäder <mail baedert org>
Date:   Mon Jan 8 21:46:16 2018 +0100

    gl renderer: Sprinkle some const around

 gsk/gl/gskglrenderer.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gsk/gl/gskglrenderer.c b/gsk/gl/gskglrenderer.c
index e243478..7668f6c 100644
--- a/gsk/gl/gskglrenderer.c
+++ b/gsk/gl/gskglrenderer.c
@@ -1670,7 +1670,7 @@ gsk_gl_renderer_create_programs (GskGLRenderer  *self,
   GskShaderBuilder *builder;
   GError *shader_error = NULL;
   int i;
-  static struct {
+  static const struct {
     const char *name;
     const char *vs;
     const char *fs;