From 349c0e1a14b8af152d1c3afd7fc009118dde3129 Mon Sep 17 00:00:00 2001
From: Marcus Comstedt <marcus@mc.pp.se>
Date: Tue, 3 Mar 2020 18:51:17 +0100
Subject: [PATCH] gal/opengl: Fix shader link state check

The old code caused a bool (size 1) to be overwritten by a GLint (size
4) causing undefined behaviour.

Fixes https://gitlab.com/kicad/code/kicad/issues/3981
---
 common/gal/opengl/shader.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/common/gal/opengl/shader.cpp b/common/gal/opengl/shader.cpp
index d78379c36b..cc09465945 100644
--- a/common/gal/opengl/shader.cpp
+++ b/common/gal/opengl/shader.cpp
@@ -101,8 +101,9 @@ bool SHADER::Link()
     programInfo( programNumber );
 
     // Check the Link state
-    glGetObjectParameterivARB( programNumber, GL_OBJECT_LINK_STATUS_ARB,
-                               (GLint*) &isShaderLinked );
+    GLint tmp;
+    glGetObjectParameterivARB( programNumber, GL_OBJECT_LINK_STATUS_ARB, &tmp );
+    isShaderLinked = !!tmp;
 
 #ifdef DEBUG
     if( !isShaderLinked )