GL_NV_geometry_program4
http://developer.download.nvidia.com/opengl/specs/GL_NV_geometry_program4.txt
GL_NV_gpu_program4
	GL_GEOMETRY_PROGRAM_NV 0x8C26
	GL_MAX_PROGRAM_OUTPUT_VERTICES_NV 0x8C27
	GL_MAX_PROGRAM_TOTAL_OUTPUT_COMPONENTS_NV 0x8C28
	void glProgramVertexLimitNV (GLenum target, GLint limit)