[C2hs] darcs patch: add ptrto directive

1 patch for repository http://code.haskell.org/c2hs: Sun Mar 24 16:21:29 CET 2013 p.balzarek@googlemail.com * add ptrto directive {#ptrto <path> #} creates a pointer into a c structure, following <path>. It behaves much like get or set, but instead of marshalling the target it returns a pointer to it. This is useful e.g. when the associated Haskell type doesn't have a Storable instance, for example SockAddr.