BUILTIN_MARKER
pbstr(BUILTIN_MARKER);
if (strncmp(defn, BUILTIN_MARKER, sizeof(BUILTIN_MARKER)-1) == 0 &&
(p = macro_getbuiltin(defn+sizeof(BUILTIN_MARKER)-1)) != NULL) {
d->defn = xstrdup(defn+sizeof(BUILTIN_MARKER)-1);