19981103
	version: checkpassword 0.80, beta.
19981121
	portability problem: some Linux systems _simultaneously_ support
		shadow passwords and non-shadow passwords. impact:
		checkpassword would see only the shadow passwords. fix:
		in doit(), use getpwnam() password if getspnam() fails
		(except with ETXTBSY). tnx to several people.
	portability problem: AIX needs -ls for getuserpw(). impact:
		couldn't compile. fix: check for -ls; also use in
		hasuserpw.h.
	portability problem: some systems incorrectly return EISDIR for
		mkdir("/",...). impact: couldn't install. fix: don't
		bother installing anything except checkpassword.
	version: checkpassword 0.81, beta.
20001115
	portability problem: PAM-based systems can put 0 into pw_passwd.
		nitwits. impact: checkpassword inspects *0 and crashes.
		fix: check for 0 and use "*" instead. tnx Sverre.
20001222
	internal: switched to new install system.
	internal: prototypes.
	internal: incorporated doit() into main().
	internal: switched to pathexec and friends.
	version: checkpassword 0.90, gamma.