Invoking make does not rebuild #include dependencies and causes undefined behaviour/segfaults.
I'd be willing to do this, but I'd possibly end up adding libpiano and libwaitress targets if it's alright. This should be as simple as specifying which files depend on which at the bottom of the Makefile...
Do you happen to have a binary that works in cygwin right now?
Modified example from GNU make manual and . Closes #221.