LINE pragmas cause trouble

[nibro]

We cannot handle LINE pragmas since they can appear anywhere at all. This was reported by NeilMitchell?:

module Foo where
{-# LINE 10 "Bar" #-}
import Baz

The only possible solution here is to treat LINE pragmas as comments, along with any other unknown pragmas.

[nibro]

I've disabled unknown pragmas, they are now simply discarded as comments. When in the next stage I retain the comments while lexing, there will be other options to handle custom pragmas via that comment stack.