windows/cygwin ghc 4.08.2 driver: DEFAULT_TMPDIR not set
The GHC driver (I suspect) reports that the DEFAULT_TMPDIR is not set, resulting in the fact that the cpp file generated by the compiler gets lost and compiling is cancelled. On the GHC homepage, I could not find this problem in the FAQ of the "Installing on Windows" section (2.2). Setting an environment variable DEFAULT_TMPDIR (either in Windows or in Cygwin Bash) doesn't help. I re-installed the previous version of GHC, and everything works as expected, so I expect this problem to be introduced in 4.08.2.