[physfs] Open patches for physfs

[Ryan C. Gordon]

> we applied all those three attached patches to the libphysfs packages in 
> Debian. Please apply them.

- Hurd/MAXPATHLEN patch is now applied to stable-2.0 and default branch.
- gcc4.4 patch was already applied to stable-2.0 and default (hasn't 
been in a release yet, but I'll hopefully do a 2.0.1 release soon).

- The doxygen patch: I _really_ dislike having to mess up the comments 
with more escape chars. Is there any way we can avoid this?

--ryan.