diff --git a/lisp/Config.sun4_solaris_gcc b/lisp/Config.sun4_solaris_gcc
index f20e9ae770ddaa2d7b5a9ca373e7b86e4407bbee..93fef6fddbba35f288d591e8c0ec6adfdaed61ce 100644
--- a/lisp/Config.sun4_solaris_gcc
+++ b/lisp/Config.sun4_solaris_gcc
@@ -1,4 +1,4 @@
-CPPFLAGS = -I/usr/include/X11 -DSOLARIS -DSVR4
+CPPFLAGS = -I/usr/openwin/include -I/usr/include/X11 -DSOLARIS -DSVR4
 CC = gcc
 CPP = gcc -E
 CFLAGS = -g