- Get ASAN working on Windows.
- Deleting directories and then recreating them with the same name in a
short period of time appears to be a no-no on Windows.
- There's no reason to call FlushFileBuffers on close() for pipes, and
it's harmful since it might block indefinitely for no good reason.
We always favor calling functions like openat(), fstatat(), etc. because
Linux, XNU, FreeBSD, and OpenBSD all elected to support them, while some
systems like Android love them so much, that they stopped supporting the
old interfaces.
This change ensures that when dirfd is actually a dirfd and not AT_FDCWD
we'll do the right thing on Windows NT. We use an API that's been around
since Vista to accomplish that.
This change also adds exponential backoff to chdir() on Windows since it
seems almost as flaky on Windows 7 as the rmdir() function.