Use official headers to define GL_ARB_texture_rectangle.

Fixing https://github.com/KhronosGroup/OpenGL-Registry/pull/149 and
https://github.com/KhronosGroup/OpenGL-Registry/pull/183 enabled
including desktop OpenGL headers without conflicts, so we no longer
have to define enums for ARB extensions ourselves.

Change-Id: I4f2e2d3b79a6f5cacf53f2a8ace78b6d124cb5d1
Reviewed-on: https://swiftshader-review.googlesource.com/19029
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/OpenGL/compiler/OutputASM.cpp b/src/OpenGL/compiler/OutputASM.cpp
index 8b20758..9ed34b2 100644
--- a/src/OpenGL/compiler/OutputASM.cpp
+++ b/src/OpenGL/compiler/OutputASM.cpp
@@ -23,6 +23,8 @@
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 #include <GLES3/gl3.h>
+#include <GL/glcorearb.h>
+#include <GL/glext.h>
 
 #include <stdlib.h>