GL_EXT_texture_mirror_clamp
http://www.opengl.org/registry/specs/EXT/texture_mirror_clamp.txt
	GL_MIRROR_CLAMP_EXT 0x8742
	GL_MIRROR_CLAMP_TO_EDGE_EXT 0x8743
	GL_MIRROR_CLAMP_TO_BORDER_EXT 0x8912
