Run cabal outside bash.
Run cabal outside bash.

See #110. [skip ci]

snowleopard/shaking-up-ghc,sdiehl/ghc,sdiehl/ghc,izgzhen/hadrian,snowleopard/hadrian,quchen/shaking-up-ghc,sdiehl/ghc,bgamari/shaking-up-ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc