As part of the 64-bit Linux nightly build, the buildbot tests building and using the C++ driver as part of a single SCons rule, "clientBuild". When that test fails, smokeRecentlyFailing will try to run the test portion of "clientBuild" after compiling the core product, but without building the driver. This causes the test to reliably fail when run as part of smokeRecentlyFailing, in the best case. In the worst, it might use old copies of executables, if the buildbot didn't clean them up before starting a new build.