patch applied (ghc): Catch exceptions on Windows, to stop it popping up dialog boxes

[Ian Lynagh]

Fri Aug  3 11:32:29 PDT 2007  Ian Lynagh <igloo at earth.li>
  * Catch exceptions on Windows, to stop it popping up dialog boxes
  Adaptated from code from Sigbjorn Finne

    M ./rts/Main.c -1 +5
    A ./rts/seh_excn.c
    A ./rts/seh_excn.h