[gtk/wip/chergert/glproto: 800/920] add missing custom.glsl source

[Christian Hergert <chergert src gnome org>]

commit 9e9051fbf63213a80852c7723f1186b4bf5711b3
Author: Christian Hergert <chergert redhat com>
Date:   Thu Jan 28 16:59:32 2021 -0800

    add missing custom.glsl source

 gsk/next/gskgldriver.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gsk/next/gskgldriver.c b/gsk/next/gskgldriver.c
index a2c707709d..bdee6867c9 100644
--- a/gsk/next/gskgldriver.c
+++ b/gsk/next/gskgldriver.c
@@ -1088,6 +1088,9 @@ gsk_next_driver_lookup_shader (GskNextDriver  *self,
       gsk_gl_compiler_set_preamble_from_resource (compiler,
                                                   GSK_GL_COMPILER_FRAGMENT,
                                                   "/org/gtk/libgsk/glsl/preamble.fs.glsl");
+      gsk_gl_compiler_set_source_from_resource (compiler,
+                                                GSK_GL_COMPILER_ALL,
+                                                "/org/gtk/libgsk/glsl/custom.glsl");
       gsk_gl_compiler_set_suffix (compiler, GSK_GL_COMPILER_FRAGMENT, suffix);
 
       /* Setup attributes that are provided via VBO */