+AS_IF([test "x$LEX" = "x:" -a ! -f $srcdir/ginsh/ginsh_lexer.cc],
+ [GINAC_WARNING([ginsh will not compile, because lex/flex is missing])])
+AS_IF([test -z "$YACCEXE" -a ! -f $srcdir/ginsh/ginsh_parser.h],
+ [GINAC_WARNING([ginsh will not compile, because yacc/bison is missing])])