Configuring OpenCL-1.0.3.4... Dependency base ==4.6.0.1: using base-4.6.0.1 Dependency bytestring ==0.10.0.2: using bytestring-0.10.0.2 Dependency mtl ==2.1.2: using mtl-2.1.2 setup-Cabal-1.16.0.3-ghc-7.6.3: The program c2hs is required but it could not be found.