-AC_PATH_PROG([FLEX], [flex])
-test "$FLEX" || AC_MSG_ERROR([flex not found])
+if test "$CVS" = "yes"; then
+ AC_PATH_PROG([FLEX], [flex])
+ test "$FLEX" || AC_MSG_ERROR([flex not found])
+
+ AC_PATH_PROG([BISON], [bison])
+ test "BISON" || AC_MSG_ERROR([bison not found])
+fi