Move Khronos OpenGL headers to top-level include directory.

Change-Id: If473b7d83e54ccdca710dffe353b539213ae2046
Reviewed-on: https://swiftshader-review.googlesource.com/5357
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>

src/OpenGL/libGLES_CM/libGLES_CM.cbp

diff --git a/src/OpenGL/libGLES_CM/libGLES_CM.cbp b/src/OpenGL/libGLES_CM/libGLES_CM.cbp
index fa28740..770fe95 100644
--- a/src/OpenGL/libGLES_CM/libGLES_CM.cbp
+++ b/src/OpenGL/libGLES_CM/libGLES_CM.cbp
@@ -123,7 +123,7 @@
 			<Add option="-DGL_APICALL=" />
 			<Add option="-DGL_GLEXT_PROTOTYPES" />
 			<Add directory="./../" />
-			<Add directory="./../include/" />
+			<Add directory="./../../../include/" />
 			<Add directory="./../../" />
 			<Add directory="./../../../third_party/LLVM/include-linux/" />
 			<Add directory="./../../../third_party/LLVM/include/" />