use 1.1 glPolygonOffset instead of glPolygonOffsetEXT
diff --git a/progs/xdemos/offset.c b/progs/xdemos/offset.c
index 158e52a..3e92e68 100644
--- a/progs/xdemos/offset.c
+++ b/progs/xdemos/offset.c
@@ -53,7 +53,7 @@
 #include <stdio.h>
 #include <string.h>
 
-/*#undef GL_EXT_polygon_offset   uncomment to use new version*/
+#undef GL_EXT_polygon_offset  /* use GL 1.1 version instead of extension */
 
 
 #ifndef EXIT_FAILURE