Attempt to compile MongoDB C++ library from http://downloads.mongodb.org/cxx-driver/mongodb-linux-x86_64-v2.0-latest.tgz resulted in dependency on PCRE which is incorrect.
See http://groups.google.com/group/mongodb-user/browse_thread/thread/c9a4129428994d4b for details.

Packages also provide binary .o files which seem extraneous there.