Function types didn't always degrade to pointers like they should. Introduced...

Function types didn't always degrade to pointers like they should.  Introduced and used Csyntax.typeconv to address this issue and reduce the number of cases in the classify functions

git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1266 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e