The +@netgroup/-@netgroup NIS password overrides can fail in
	some cases due to a subtle bug. Specifically, if you override
	an NIS user's shell, /usr/bin/login and /usr/bin/su (and probably
	other commands) can end up with bogus data for the pw_shell
	member of the passwd structure *if* the do an endpwent(),
	thereby preventing logins.

	This happpens because the text fields in the passwd structure
	(pw_name, pw_passwd, pw_gecos, pw_class, pw_dir and pw_shell)
	are returned to the calling program as pointers to dycamically
	allocated buffers, rather than pointers to static buffers as
	they should be. Once endpwent() is called, the dynamic buffers
	are free()ed, which invalidates the data returned by the
	library functions.

Fix: This is a context diff for /usr/src/lib/libc/gen/getpwent.c
	that fixes the problem. A more elegant solution would be
	preferable, and I intend implement one for 2.1 just as soon
	as the code lockout for 2.0.5 is lifted.

How-To-Repeat: 
	1) enable NIS
	2) put an entry in the master.passwd file that overrides
	   the shell field for a user in the NIS database, like this:
	   +testuser:::::::::/bin/csh
	3) attempt to login as user 'testuser'. The result will be
	   that /usr/bin/login will end up with some random value
	   for pw_shell and the login will fail.