More autoconf hacking: use same machinery to find zlib as for openssl and libevent. Have unified library finder include setup for --with variable. Start trying to suggest to the user what packages they should install if finding the library fails.
svn:r9945
Macro-ize our "search for a library and find out how to link against it" code. This will help make our handling of libevent and openssl more similar, and with any luck better. Not pushing to main branch until after 0.1.2.
svn:r9726