When trying to build with the latest version of glog, the build system spews out a really long list of errors. The glog library version should probably be checked in cmake.

Apparently, glog has also been labeled as deprecated. The developers suggest either using a community-maintained API-compatible library ng-log, or the one maintained by Google (abseil-cpp). It's also possible to simply include glog 0.6 in the external submodules.