I've got the Coda server and support stuff building under Mac OS X 
10.0 (and thus it should work on Darwin too).  The basic changes for the 
patches are:

- Added Mach VM support for testing if blobs of memory are accessible
- Avoid using 'common' symbols -- declare stuff extern instead.  Mac OS 
X doesn't allow common symbols in shared libraries.
- Small other tidbits
- Since coda/configs includes config.guess and config.sub and they are 
out of date, I copied the versions from /usr/libexec on Darwin.  You 
might just want to update these from the latest version of autoconf.

   If any more explanation is needed for these patches, please let me 
know and I'll let you know what I was thinking :)

   The diffs are at http://www.omnigroup.com/~bungi/coda-osx.diff and the 
script that I used to build stuff is at 
http://www.omnigroup.com/~bungi/Coda-MacOSX-Build

  Thanks!

-tim