GL_SGIX_slim
https://www.khronos.org/registry/OpenGL/extensions/SGIX/SGIX_slim.txt
GL_SGIX_slim

	GL_PACK_MAX_COMPRESSED_SIZE_SGIX 0x831B
	GL_SLIM8U_SGIX 0x831D
	GL_SLIM10U_SGIX 0x831E
	GL_SLIM12S_SGIX 0x831F