patch applied (ghc): break by function: make sure we get the correct file

[Simon Marlow]

Fri Apr 27 07:45:54 PDT 2007  Simon Marlow <simonmar at microsoft.com>
  * break by function: make sure we get the correct file
  Sometimes parts of a source file come from different places due to
  preprocessing, and the lines can overlap.

    M ./compiler/ghci/InteractiveUI.hs -5 +14