Hadrian inexplicably rebuilds when output is redirected
Hadrian somehow includes knowledge of whether stdout/stderr are a terminal or not in its recompilation check. For instance,
$ hadrian/build-cabal -j9
[build proceeds, finishes]
$ hadrian/build-cabal -j9 >& log
[build starts afresh, finishes]
$ hadrian/build-cabal -j9
[build yet again starts afresh, finishes]
This is a rather serious issue as it makes debugging extremely painful.