Use process createPipe

[phadej]

cc @Mistuke

This doesn't yet work due

Unit Tests
  Distribution.Compat.CreatePipe
    Locale Encoding:                                                                      FAIL
      tests/UnitTests/Distribution/Compat/CreatePipe.hs:19:
      createPipe should support Unicode roundtripping
      expected: "\252"
       but got: "\195\188"

Compare:

createPipeInternal :: IO (Handle, Handle)
createPipeInternal = do
    (readfd, writefd) <- Posix.createPipe
    readh <- Posix.fdToHandle readfd
    writeh <- Posix.fdToHandle writefd
    return (readh, writeh)

and

createPipe = do
    (readfd, writefd) <- Posix.createPipe
    readh <- fdToHandle readfd
    writeh <- fdToHandle writefd
    hSetEncoding readh localeEncoding
    hSetEncoding writeh localeEncoding
    return (readh, writeh)
  where
    _ = callStack

---

I will think how to rip this locale dependency off. As we use this to read stderr and stdout using single pipe, we really should just read ByteString and don't care of what kind of "crap" test suites give us, i.e. simply pass it through.