Pine has historically built against an internal copy
of the c-client library, however c-client development
has progressed beyond what is shipped with pine.
(It would appear that all new development work is
being done via UW's imap server codebase.) This change
allows pine to utilize improvements/bugfixes in the
c-client library. A consequence of this change is
that the recently reported vulnerability to BugTraq
regarding malformed X-keywords header has been fixed.
