Currently, Evergreen only produces 64-bit builds of the driver. We should add several variants which ensure that the driver can compile in 32-bit mode and run on 32-bit platforms.

The mongo-c-driver project accomplishes this on Windows through "Visual Studio 14 2015" CMake generator (as opposed to the "Visual Studio 14 2015 Win64" generator), and on Unix platforms by specifying the "-m32 -march=i386" compiler flags. We could also investigate whether the toolchains on any of the 32-bit host types provided by Evergreen (rhel55-32? windows-32?) meet our minimum toolchain requirements.