You are right that boost is not touched very often, but I don't want to think about that, I want the build system to do that for me. Adding 20 seconds to every build is far better than spending two hours to debug a non-existing bug!
OK. Here is the deal. I have changed the logic of scons so that boost headers will be excluded from the dependency tree only when boost=system. That is to say, developers can choose to install system boost libraries and enjoy faster start (16s null build vs 14s for autotools), or use included boost as usual (29s null build). Rebuilding will be as reliable as before. At least there is a way to match autotools regarding null build time. Cheers, Bo
