[gtk/wip/chergert/gdk-macos-gl-renderer: 5/6] glsl: tweak preamble to work on Apple glsl compiler

[Christian Hergert <chergert src gnome org>]

commit 1ae769728b0fe0d91504f321fbfd58c530d6c8d4
Author: Christian Hergert <chergert redhat com>
Date:   Wed Oct 21 17:07:44 2020 -0700

    glsl: tweak preamble to work on Apple glsl compiler

 gsk/resources/glsl/preamble.fs.glsl | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/gsk/resources/glsl/preamble.fs.glsl b/gsk/resources/glsl/preamble.fs.glsl
index 85b11c013e..c2cd1cdc29 100644
--- a/gsk/resources/glsl/preamble.fs.glsl
+++ b/gsk/resources/glsl/preamble.fs.glsl
@@ -5,10 +5,9 @@ uniform float u_alpha;// = 1.0;
 uniform vec4 u_viewport;
 uniform vec4[3] u_clip_rect;
 
-#if GSK_GLES
-#elif GSK_LEGACY
+#if defined(GSK_LEGACY)
 _OUT_ vec4 outputColor;
-#else
+#elif !defined(GSK_GLES)
 _OUT_ vec4 outputColor;
 #endif