patch applied (cabal): Refactor unlit code to improve error and line pragma handling

[Duncan Coutts]

Sat Dec 29 17:25:30 PST 2007  Duncan Coutts <duncan at haskell.org>
  * Refactor unlit code to improve error and line pragma handling
  And to make it more like the original code that classified lines
  separately from checking and transforming them.

    M ./Distribution/Simple/Hugs.hs -3 +7
    M ./Distribution/Simple/PreProcess.hs -1 +1
    M ./Distribution/Simple/PreProcess/Unlit.hs -55 +86