update misc notices

-llber is available for -llunicode.  Add -llber to ucgendat
(to pick up snprintf).

  - librewrite, for string rewriting; it may be used in back-ldap
    by configuring with '--enable-rewrite'. It must be used in
    back-meta. There's a text file, 'libraries/librewrite/RATIONALE',
    that explains the usage and the features. More comprehensive
    documentation will follow.
  - enhancements of back-ldap (ITS#989,ITS#998,ITS#1002,ITS#1054 and ITS#1137)
    including dn rewriting, a fix to group acl matching and so
  - back-meta: a new backend that proxies a set of remote servers
    by spawning queries. It uses portions of back-ldap and the rewrite
    capabilities of librewrite. It can be compiled by configuring
    with `--enable-ldap --enable-rewrite --enable-meta'.
    There's a text file, 'servers/slapd/back-meta/Documentation', that
    describes the main features and config statements.

Note: someone (Kurt?) should run 'autoconf' and commit 'configure' as
my autoconf version must be different: my configures contain a number
of differences and I didn't feel comfortable in adding them :)

subdirectories; add explicit dependencies for subdirs that need them.

	Likely broke things for non-posix threadings....

Update -lldap_r implementation to:
	remove attribute support
	hide thread detachment
	provide concurrency accessors
	provide initialization function
	fix gethostby{addr,name}_r codes (not coverred by HAVE_REENTRANT_FUNCTIONS)
Update servers/libraries to use ldap_pvt_thread_ calls.
Cleanup server codes (no #ifdef HAVE_PTHREAD_THIS or _THATs)!
Removed -llthread

will eventually be very last).  Add lthread/lutil to libldap_r test
program linkage.