Move GLES20 source into standard locations Move Khronos headers into their respective components, to be exported by each. Remove hostthreadadapter as nothing outside of the vghwapiwrapper, which now contains the code, needs it

/*
 * This file is part of the Mingw32 package.
 *
 * This file.h maps to the root fcntl.h
 * TODO?
 */
#include <fcntl.h>