A few fixes to the Xcode projects for OS X.

- Add the Japanese modem source files to the project so that it actually builds successfully.
- Adjust a few variables so that it should work regardless of Xcode version and SDK versions installed (hopefully).

git-svn-id: svn+ssh://svn.code.sf.net/p/yabause/code/trunk@3233 d7be59e3-070e-4b9a-85a1-4646befae34d