Ben Boeckel <ben.boeckel_at_[hidden]> writes:

> Personally, my gut reaction is that this belongs at the build executor
> level, not the compiler.

I believe what Mathias is referring to (and what we call "ignorable
changes" such as whitespace/comment changes, etc), are quite natural
to handle by hashing pp-tokens (including their position, if debug
info is enabled) and which does fit well into the pre-scan. At least
that's how we do it in build2.