Add config.h.in to shake-build/cfg. This file is needed for Rules.Generators.GhcAutoconfH.
Add config.h.in to shake-build/cfg. This file is needed for Rules.Generators.GhcAutoconfH.

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