cached_realpath
const char *abspath = cached_realpath(argv0, pathbuf);
const char *cached_realpath(const char *, char *);
cached_realpath(p, latestdir);
if (cached_realpath(tname, buf) != NULL) {
if (cached_realpath(dname, objdir_realpath) != NULL)
cached_realpath(p, fname); /* clean it up */
rp = cached_realpath(word.start, rbuf);