I cannot try this because I do not have ordrules.h, but I don't see how this can happen: the line register_foreign_inttype("tcflag_t",sizeof(tcflag_t),(tcflag_t)-1<=(tcflag_t)0); is generated by (def-c-type tcflag_t) and there is no such line in the lisp file you attach. please file a clisp bug report, see http://clisp.cons.org/impnotes/faq.html#faq-bugs thanks.