Common C++ 2 1.3.20: http://sourceforge.net/projects/cplusplus/
ccRTP 1.3.5: http://sourceforge.net/projects/cplusplus/
libosip 2.2.1: http://savannah.gnu.org/projects/osip/

if you want zeroconf:
mDNSResponder87: http://developer.apple.com/darwin/projects/bonjour/

See tools/config.sh for more details