SDL2 This will cause SDL 2 to be used instead of SDL 1. You will need to link to the correct libraries.
UNALIGNED_MEMORY This is necessary if the host isn’t little endian, like the Emscripten build
BOXEDWINE_ZLIB Will allow the file system to be in a zip file (-zip command line argument). This requires that you link against zlib.
BOXEDWINE_HAS_SETJMP Will allow memory exception to be caught, this should be used for all builds. Emscripten doesn’t use it because it slows things down, but this also means some games won’t work.
BOXEDWINE_MSVC Should use this on Windows platform, without this, the code will assume Linux compatible headers and standard c functions
BOXEDWINE_OPENGL_SDL Enables OpenGL support
BOXEDWINE_RECORDER enabled -record and -automation command line arguments. I use this to automate some test, probably not super useful for any other reason.
BOXEDWINE_DYNAMIC enables the dynamic recompiler code, an additional define is required for the platform specific code, currently only x86 is supported: BOXEDWINE_DYNAMIC32