* add support for YP "master.passwd.by*" (master.passwd in YP, including
pw_passwd) and "passwd.adjunct.by*" (SunOS `secure' maps (?)), based
on code in FreeBSD and partially from OpenBSD.
this is only used if euid == 0.
with this, the YP "passwd.by*" maps can have `*' in the pw_passwd field.
* use pw_scan() to parse YP "passwd.by*" and "master.passwd.by*" entries
XXX: i didn't test the "passwd.adjunct" support...