Change type to enum. Change storage class to static. Adjust comments.
(read_etc_passwd): Set passwd_state to different values when loaded
from file in contrast to being emulated.
(search_for): Return default passwd entry if passwd is emulated or
it's a request for the current user. Otherwise return NULL.
* spawn.cc (_spawnve): Ditto.
* passwd.cc: Remove static from `passwd_in_memory_p'.
(read_etc_passwd): Remove static.
* uinfo.cc: Move global declaration of `read_etc_group' and
`group_in_memory_p' into `uinfo_init'.
(internal_getlogin): Try to get SID from current process first.
(uinfo_init): Don't set uid and gid if `myself' has a valid SID.
Only load /etc/passwd and /etc/group in that case.