diff --git a/configure.in b/configure.in
index a8eb98a2..92e899db 100644
--- a/configure.in
+++ b/configure.in
@@ -3,6 +3,7 @@ AC_INIT(reduce.c)
 AC_PROG_CC
 AC_PROG_CPP
 AC_PROG_INSTALL
+AC_CONST
 AC_MINIX
 AC_ISC_POSIX
 AC_STDC_HEADERS