Do not assume that mode_t uses the traditional octal encoding. E.g. "chmod 1 FOO" should set the other-execute bit of FOO even if S_IXOTH != 1. (SUID, SGID, SVTX, RUSR, WUSR, XUSR, RGRP, WGRP, XGRP, ROTH, WOTH, XOTH, ALLM): New macros. (S_ISUID, S_ISGID, S_ISVTX, S_IRUSR, S_IWUSR, S_IXUSR, S_IRGRP, S_IWGRP, S_IXGRP, S_IROTH, S_IWOTH, S_IXOTH): Use them. (S_ISGID): Fix typo; it was defaulting to the same value as S_ISUID. (S_IRWXU, S_IRWXG, S_IRWXO): Specify defaults in terms of the above. (mode_compile): No need to use uintmax_t; unsigned long is long enough. Don't bother to get suffix since we don't use it.