We do "kind of that": Our source is split across various cpp files to keep it well organized. Our build scripts then generates a single cpp file with ~30 #incl

We do "kind of that": Our source is split across various cpp files to keep it well organized. Our build scripts then generates a single cpp file with ~30 #includes. Compilation of the 11Mb object file takes about 30s and requires at most 1GB memory (the lib is not that huge, 20kloc), but I think when we started on it, the build took a few minutes for the lib alone. So we save some dev time, but building all unit test executables still takes an additional 1m30s. So that's only a minor improvement. But I think the real gain is a much better optimization (the architecture of the lib is great to maintain and bugs are at least critical or might even have a lethal impact; there is a lot of potential for inlining/LTO).