GL_EXT_texture_mirror_clamp
http://oss.sgi.com/projects/ogl-sample/registry/EXT/texture_mirror_clamp.txt
	GL_MIRROR_CLAMP_EXT 0x8742
	GL_MIRROR_CLAMP_TO_EDGE_EXT 0x8743
	GL_MIRROR_CLAMP_TO_BORDER_EXT 0x8912