GLX_SGIX_fbconfig
http://oss.sgi.com/projects/ogl-sample/registry/SGIX/fbconfig.txt
	GLX_WINDOW_BIT_SGIX 0x00000001
	GLX_RGBA_BIT_SGIX 0x00000001
	GLX_PIXMAP_BIT_SGIX 0x00000002
	GLX_COLOR_INDEX_BIT_SGIX 0x00000002
	GLX_SCREEN_EXT 0x800C
	GLX_DRAWABLE_TYPE_SGIX 0x8010
	GLX_RENDER_TYPE_SGIX 0x8011
	GLX_X_RENDERABLE_SGIX 0x8012
	GLX_FBCONFIG_ID_SGIX 0x8013
	GLX_RGBA_TYPE_SGIX 0x8014
	GLX_COLOR_INDEX_TYPE_SGIX 0x8015
	GLXFBConfigSGIX* glXChooseFBConfigSGIX (Display *dpy, int screen, const int *attrib_list, int *nelements)
	GLXContext glXCreateContextWithConfigSGIX (Display* dpy, GLXFBConfig config, int render_type, GLXContext share_list, Bool direct)
	GLXPixmap glXCreateGLXPixmapWithConfigSGIX (Display* dpy, GLXFBConfig config, Pixmap pixmap)
	int glXGetFBConfigAttribSGIX (Display* dpy, GLXFBConfigSGIX config, int attribute, int *value)
	GLXFBConfigSGIX glXGetFBConfigFromVisualSGIX (Display* dpy, XVisualInfo *vis)
	XVisualInfo* glXGetVisualFromFBConfigSGIX (Display *dpy, GLXFBConfig config)
	typedef XID GLXFBConfigIDSGIX
	typedef struct __GLXFBConfigRec *GLXFBConfigSGIX