when possible since that allows us to support the stay_setuid option and
we always know exactly what the semantics will be (various Linux kernels
have broken POSIX saved uid support).
call initgroups() if the target user was root. Now it always calls
initgroups() unless the -P command line option or the "preserve_groups"
sudoers option is set. Idea from TJ Saunders.
Rename set_perms_saved_uid() -> set_perms_posix()
Make set_perms_setreuid simply be set_perms_fallback() and simply include
the appropriate function at compile time (setreuid() vs. setuid()).
o stay_setuid - sudo will remain setuid if system has saved uids or setreuid(2)
o env_reset - reset the environment to a sane default
o env_keep - preserve environment variables that would otherwise be cleared
No longer use getenv/putenv/setenv functions--do environment munging by hand.
Potentially dangerous environment variables can be cleared only if they
contain '/' pr '%' characters to protect buggy programs.
Moved environment routines into env.c (new file)
if available.
Added stay_setuid option for systems that have libraries that perform
extra paranoia checks in system libraries for setuid programs (ie:
anything with issetugid(2)).
