The static libmongoclient library is not useable at all on windows (see CXX-59), and requires special handling on ELF targets (via --whole-archive). There are probably similar issues on Darwin (though maybe not: see -all_load vs -noall_load).

Currently the build system defaults to building the static library, and only builds the shared library when requested. We should reverse this, and always build the shared library, and only enable the static library when explicitly requested.