Log Message:
Import hs-cpphs-1.6 as wip/hs-cpphs.

cpphs is a liberalised re-implementation of cpp, the C pre-processor,
in Haskell. This version of cpp is pretty-much feature-complete, and
compatible with the -traditional style. It has two main modes:

    * conditional compilation only (--nomacro),
    * and full macro-expansion (default).