m4_warnx
m4_warnx("numeric overflow in expr: %s", yytext);
m4_warnx("error in number %s", yytext);
m4_warnx("error in number %s", yytext);
extern void m4_warnx(const char *, ...);
extern void m4_warnx(const char *, ...);
m4_warnx("No subexpression %d", n);
m4_warnx("Too few arguments to patsubst");
m4_warnx("Too few arguments to regexp");