diff --git a/configure.ac b/configure.ac
index d09fec9d..355cf0b4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -659,5 +659,7 @@ CFLAGS="$SAVED_CFLAGS"
 AC_SUBST(AM_LDFLAGS)
 LDFLAGS="$SAVED_LDFLAGS"
 
+AC_PROG_YACC
+
 # autoconf should create a Makefile.
 AC_OUTPUT(Makefile)