use_mangled_mesa

Disallowed. See CMake Policy CMP0030.

Copy mesa headers for use in combination with system GL.

use_mangled_mesa(PATH_TO_MESA OUTPUT_DIRECTORY)

The path to mesa includes, should contain gl_mangle.h. The mesa headers are copied to the specified output directory. This allows mangled mesa headers to override other GL headers by being added to the include directory path earlier.