SDL is now built with the 32/64 bit mingw cross-compiler from:
http://mingw-w64.org

On Mac OS X, you can install this using MacPorts:
https://www.macports.org
... and install the mingw-w64 package

Once you have the cross-compilation tools available, you can get
the scripts cross-configure.sh and cross-make.sh and use them as
you would normally use configure and make.

These scripts are available from:
	http://www.libsdl.org/extras/win32/cross/cross-configure.sh
	http://www.libsdl.org/extras/win32/cross/cross-make.sh

Enjoy!