Make streamed roms working for non-windows systems.

git-svn-id: https://svn.code.sf.net/p/desmume/code/trunk@4819 5577840e-afb3-4e59-9ef3-2b7f898b1952
Cocoa Port:
- Add support for the new stream loaded ROM feature.
- Update ROM loading code to latest core code.

git-svn-id: https://svn.code.sf.net/p/desmume/code/trunk@4820 5577840e-afb3-4e59-9ef3-2b7f898b1952