Log Message:
update to gnutls-1.0.23

Noteworthy changes since the last release:

- Replace GNU LD version script with Libtool -export-symbols-regex,
  from Joe Orton <joe at manyfish.co.uk>.
- Copy libtasn1 has been updated to version 0.2.11.
- Corrected the write of CRL distribution points.
- It is now possible to generate PKCS#12 structures without private
  keys using "certtool --to-p12", suggested by Fabian Fagerholm
  <fabbe at paniq.net>.