The line:
> cabal: The program c2hs is required but it could not be found.
is pretty clear about the source of error. You have to install c2hs first and make sure its in PATH. Use either some packaged version of c2hs or "cabal install c2hs".

Best regards,
Krzysztof Skrzętnicki

On Thu, Dec 6, 2012 at 11:48 AM, Trung Quang Nguyen <trungnq97@gmail.com> wrote:
The program c2hs is required but it could not be found.