[C2hs] patch applied (c2hs): Change handling of gnu __extension__ keyword

[Duncan Coutts]

Mon May 29 06:32:54 PDT 2006  Duncan Coutts <duncan.coutts at worc.ox.ac.uk>
  * Change handling of gnu __extension__ keyword
  GNU C allows __extension__ in various places we don't at the moment.
  This is a bit tricky to follow exactly without getting lots of
  shift/reduce conflicts. So what I've got here is a compromise.
  Sadly allowing __extension__ in expressions conflicts with it's use
  in declerations. So, instead of allowing __extension__ in any
  declaration I only allow it in an external decleration (top level).
  Fortunately I think that almost all uses of __extension__ in
  declarations are actually external declarations. So I think this is
  the right compromise.

    M ./c2hs/c/CParser.y -18 +9