Another CPP gotcha for the manual

[Herbert Valerio Riedel]

Hello Malcolm,

On 2013-11-04 at 10:28:27 +0100, Malcolm Wallace wrote:
> Of course, cpphs solved this problem nearly a decade ago.

Btw, what has been the reason it hasn't been adopted as bundled `cpp`
replacement in the GHC distribution in the past? (if it remains a
separate executable, its GPL licence shouldn't be an issue -- after all,
ghc relies on the gcc executable which is GPL'ed too)

cheers,
  hvr