make option suggestion

[Simon Marlow]

John Meacham wrote:
> I would definitely like something like this.
> like
> 
> {-# PREPROCESS drift-ghc #-}
> 
> to specify the file should be preprocced by drift-ghc. 

I worry that putting details of the build procedure into the source file will 
lead to problems.  Often build parameters need to be configurable, eg. do I use 
happy's -g option or not?  It depends what Haskell compiler you're using.  Build 
systems are usually well suited to doing configurable things.  Also, we don't 
really want pathnames leaking into source files.

So we're left with just specifying the kind of preprocessor to use, as in the 
example above.  It's certainly more general than the existing scheme of looking 
at the file extension, but I wonder whether it's worth it.

Cheers,
	Simon