diff --git a/modules/gfx/src/glext_include.hh b/modules/gfx/src/glext_include.hh
index 183f6112cbd9bfb91bf57323faf759cad3e3918f..557dcb36045c75542d1fa9df5d24edecfc47a1f5 100644
--- a/modules/gfx/src/glext_include.hh
+++ b/modules/gfx/src/glext_include.hh
@@ -29,7 +29,7 @@
 #include <ost/config.hh>
 
 #if OST_SHADER_SUPPORT_ENABLED
-#ifdef OST_MESA_SUPPORT_ENABLED
+#if OST_MESA_SUPPORT_ENABLED
 #  define OST_GL_VERSION_2_0 1
 #  define GL_GLEXT_PROTOTYPES 1
 #  include <GL/gl.h>
diff --git a/modules/gfx/src/shader.cc b/modules/gfx/src/shader.cc
index c3b8b1d79ae42f3a58aeda6f1c8606a5bd8dc389..80d375ce457d7aa0b0f5e0ea35e75e18c9a1e967 100644
--- a/modules/gfx/src/shader.cc
+++ b/modules/gfx/src/shader.cc
@@ -51,7 +51,7 @@ Shader::Shader():
   shader_program_map_()
 {
   if(!OST_GL_VERSION_2_0) {
-    LOG_VERBOSE("OpenGL version smaller 2.0, deactivating shader functionality");
+    LOG_VERBOSE("OpenGL version less than 2.0, deactivating shader functionality");
   }
 }
 
@@ -59,7 +59,9 @@ Shader::Shader():
 void Shader::PreGLInit() 
 {
 #if !defined(__APPLE__)
-#if !defined(OST_MESA_SUPPORT_ENABLED)
+#if OST_MESA_SUPPORT_ENABLED
+  // skip glew initialization
+#else
   GLenum err = glewInit();
   if (GLEW_OK != err) {
     LOG_ERROR("glew failure: " << glewGetErrorString(err));