Temporary files collision

[jacereda]

I'm getting occasional (like 1 out of 50 builds or so) temporary file collisions when using Shake with fsatrace on machines with a high core count (64 logical cores).

I noticed the comment in the temp file creation referencing https://ghc.haskell.org/trac/ghc/ticket/10731 that seems to be closed now and will be testing the following change for a while.

newTempFileWithin tmpdir = do
  (path, h) <- openTempFile tmpdir "ext.tmp"
  hClose h
  pure (path, removeFile path)