0.pre7.103:

	rewrote LOOKUP-LOGIN-NAME to use getpwuid() instead of
		parsing "/etc/passwd" and then trying to speed up that
		fundamentally slow process by maintaining a
		fundamentally bogus cache of previous lookup results...
	...deleted *UID-HASH-TABLE*
	...deleted GET-GROUP-OR-USER-NAME
	...deleted GET-GROUP-OR-USER-NAME-AUX
	...defined uid_username() in wrap.c to encapsulate the
		C-level struct dereferencing
	...factored the C-to-Lisp conversion logic out of POSIX-GETCWD,
		anticipating reusing it in LOOKUP-LOGIN-NAME
	...rewrote LOOKUP-LOGIN-NAME to call uid_username(), and
		renamed it to UID-USERNAME