I dug out some 5-year-old C++ code recently, about 20kloc. I was expecting it would compile instantly on modern hardware like my Surface Book. It's taking about 12 minutes to build on travis with some of the worst offenders disabled (the SWIG-generated bindings were particularly slow IIRC), and a local build feels like it takes longer: https://travis-ci.org/PembrokeNS/sakusen