A build "--without-server" fails if using "--with-ssl" (YaSSL)

The problem was the lack of directory "extra" in a build
which did not include the server.

configure.in:
  1) Ensure "extra" is in the list of client directories.
  2) Always handle the client directories first, as they will
     be contained in every build (we have client-only, but not
     server-only).