a change in /etc.
* cygheap.h (struct init_cygheap): Add member `etc_changed_h'
and method `etc_changed'.
* grp.cc (enum grp_state): Eliminate.
(class grp_check): Ditto.
(group_state): Define as `class pwdgrp_check'.
(parse_grp): Remeber path and modification time of /etc/group file.
* passwd.cc (enum_pwd_state): Eliminate.
(class pwd_check): Ditto.
(passwd_state): Define as `class pwdgrp_check'.
(read_etc_passwd): Remember path and modification time of /etc/passwd
file.
* pwdgrp.h: New file.
(enum pwdgrp_state): Substitutes `pwd_state' and `grp_state'.
(class pwdgrp_check): Substitutes `pwd_check' and `grp_check'.