The BerkeleyDB 6.0 btree comparison function takes an additional argument,
a size_t reference, currently unused.
Move to autoconf 1.14; subdir-objects means we have to copy the compression
file and build it locally, we're already building the standard version of it
in the source location.
Clean out both the top-level directory and build_posix, remove the
Makefile and a couple of additional configure output files when we
clean.
autoconf 1.14, add subdir-objects.
add --with-berkeleydb=DIR as a configuration command instead of
squirreling around in /usr/local.
Fix the Java build for automake 1.14.

refs #841, #599
Maintain compatibility with older versions of BDB.

refs #841
Merge pull request #841 from wiredtiger/autoconf

Autoconf 1.14