suggestion: add a .ehs file type

[Duncan Coutts]

On Fri, 2007-11-23 at 01:50 +0100, Wolfgang Jeltsch wrote:

> Dont’t just think in terms of single modules.  If I have a Cabal package, I 
> can declare used extensions in the Cabal file.  A user can decide not to 
> start building at all if he/she sees that the package uses an extension 
> unsupported by the compiler.

Indeed. In theory Cabal checks all the extensions declared to be used by
the package are supported by the selected compiler. In practise I'm not
sure how well it does this or what kind of error message we get.

Duncan