[physfs] Mac OS X usage … probably missing something obvious

[Ryan C. Gordon]

> I thought perhaps that OS X's supplied version of Zlib was not supported, so I added the Zlib123 code to the project which is supplied with PhysFS. Same result.
>
> What step am I missing here, folks. I'm extremely confused.

If you built PhysicsFS yourself (just dropped the C files into your 
project), then you'll need to add some preprocessor macros. If all you 
want is .zip support, make sure the files are compiled with 
PHYSFS_SUPPORT_ZIP defined to 1 (there is also PHYSFS_SUPPORT_WAD, etc, 
for other archive types).

You can use the system-provided zlib on Mac OS X instead of our zlib123 
directory, as it's reliably installed on every system.

--ryan.