Now to sort out configure enable/with options.

Added NO_THREAD support to configure.in.  (Still need thread lib detection)

	SHA1 support is contributed by Daniel J. Gregor <dj@gregor.com>
	MD5 support is contributed by me <kurt@OpenLDAP.org>
	Uses public domain MD5 routines
	Uses ISC/IBM freely redistributable Base64 routines
	SHA1 support requires external SHA1 routines

Patch provided by dj@gregor.com.

Patch provided by dj@gregor.com.

	adds POSIX RegEx (and removes BSD re_comp/re_exec) support.
* POSIX RegEx is not currently included in the distribution, however
	we will probably add Henry Spencer's REGEX library soon.
* ACL Group functionality is also included in this merge!