GL_EXT_packed_depth_stencil
http://www.opengl.org/registry/specs/EXT/packed_depth_stencil.txt
	GL_DEPTH_STENCIL_EXT 0x84F9
	GL_UNSIGNED_INT_24_8_EXT 0x84FA
	GL_DEPTH24_STENCIL8_EXT 0x88F0
	GL_TEXTURE_STENCIL_SIZE_EXT 0x88F1
