Should you delete the work dir, or is it safe to resume? Like, do the build scripts take into consideration the start and stop of the build of a file, or does it just know what files have an output?

Like there's


That's going to make a.o, right? I think...

Does the script know that cc a.c returned 0, or does it not care, and just checks for the existence of a.o?
That's typically the compiler that takes care of this. But I generally don't take any chances and just do make clean and start over.