- The OS X specific flags must not be set when cross compiling. Check for a
MinGW compiler on OS X before adding them.
- Do not set CC explicitly in chinachippatcher, it will be set from Rockbox
Utility's Makefile.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@31527 a1c6a512-1295-4272-9138-f99709370657