diff --git a/src/test/X11/makefile b/src/test/X11/makefile
index 7a9e324f..5a390a4e 100644
--- a/src/test/X11/makefile
+++ b/src/test/X11/makefile
@@ -1,3 +1,5 @@
+#for old systems like RHEL4 use
+#CFLAGS=-L/usr/X11R6/lib -lX11
 CFLAGS=-lX11
 export CFLAGS