* src/newgrp.c, src/chfn.c, src/groupmems.c, src/usermod.c,

	* src/newgrp.c, src/chfn.c, src/groupmems.c, src/usermod.c,
	src/userdel.c, src/chpasswd.c, src/grpck.c, src/gpasswd.c,
	src/groupdel.c, src/chgpasswd.c, src/vipw.c, src/useradd.c,
	src/su.c, src/groupmod.c, src/passwd.c, src/pwck.c,
	src/groupadd.c, src/chage.c, src/login.c, src/faillog.c,
	src/sulogin.c, src/chsh.c, src/pwconv.c: Added splint annotations.
	* src/userdel.c, src/pwconv.c, src/lastlog.c, src/grpck.c,
	src/vipw.c, src/groupmod.c, src/passwd.c, src/pwck.c, src/login.c,
	src/sulogin.c, src/usermod.c: Use return instead of exit at the
	end of main().
	* src/gpasswd.c, src/passwd.c, src/faillog.c: Use the exitcodes.h
	exit codes.
	* src/chpasswd.c: Added missing ||.
	* src/nologin.c: Do not include exitcodes.h.
	* src/nologin.c: Added brackets.
	* src/nologin.c: Avoid assignments in comparisons.