Asynchronously monitors specified directory for changes and passes notifications to provided callback.
Dependency for index-while-building.
Differential Revision: https://reviews.llvm.org/D58418
I'm not sure how, but I think this commit broke building with ninja at least on some platforms.
I saw the same error locally and it bisected to this revision.
The equivalent line in a good build.ninja looks similar though... I can't dig into it right now, it's pretty late.