added missing definitions for OpenGL Enums on OSX

libs_required/ACG/GL/removedEnums.hh

@@ -7,7 +7,26 @@
 * A list of enums, which were removed for core profiles.
 * list was obtained by parsing gl.xml from https://github.com/KhronosGroup/OpenGL-Registry/blob/master/xml/gl.xml
 * on 27.2.2018
+*
+* unknown identifiers for OSX were manually defined using ifdef
 */
+
+#ifndef GL_CLAMP_VERTEX_COLOR
+#define GL_CLAMP_VERTEX_COLOR 0x891A
+#endif
+#ifndef GL_CLAMP_FRAGMENT_COLOR
+#define GL_CLAMP_FRAGMENT_COLOR 0x891B
+#endif
+#ifndef GL_ALPHA_INTEGER
+#define GL_ALPHA_INTEGER 0x8D97
+#endif
+#ifndef GL_TEXTURE_LUMINANCE_TYPE
+#define GL_TEXTURE_LUMINANCE_TYPE 0x8C14
+#endif
+#ifndef GL_TEXTURE_INTENSITY_TYPE
+#define GL_TEXTURE_INTENSITY_TYPE 0x8C15
+#endif
+
 std::unordered_set<GLenum> removedEnums = {
 GL_CURRENT_BIT,
 GL_POINT_BIT,