# ifdef HAVE_X11_EXTENSIONS_XF86VMODE_H
# include <X11/extensions/xf86vmode.h>
# endif
+/* If GLX is too old, we will fail during runtime when multisampling
+ is requested, but at least freeglut compiles. */
+# ifndef GLX_SAMPLE_BUFFERS
+# define GLX_SAMPLE_BUFFERS 0x80A8
+# endif
+# ifndef GLX_SAMPLES
+# define GLX_SAMPLES 0x80A9
+# endif
#endif