to validate input dn's BEFORE sending dn's to server.
Also fixed getfilter to use REG_EXTENDED|REG_NOSUB.  (and fixed one
case where REG_BASIC was still used).
s/strdup/LDAP_STRDUP/
Added ldap_pvt_str2lower/upper

reflect its purpose.  Modify switch to support REG_EXTENDED expressions.
Use REG_EXTENDED instead of REG_BASIC everywhere.
Modify <ac/regex.h> to support <gnuregex.h> for testing purposes.
Requires: env CPPFLAGS="-DHAVE_GNUREGEX_H=1" LIBS=-lgnuregex ./configure

attribute syntaxes using syntax description in addition to syntax OID.
Removed all whitespace from syntax descriptions.

Test008 now runs without leak.

(test001-populate runs without leak)
Free global entry string buffer on shutdown.