Add basic support for other platforms about hax

[iraizo]

Yeah will do when I get Freetime

[7ap]

If I remember correctly, memlib has some cross-platform support so that shouldn't be an issue. The hax::main attribute definitely would need to be cross platform as it's a very core part of the framework, I'll need to keep this in mind while working on #2.

[iraizo]

impl memoryread/write for darwin wouldn't be that hard I'd say but any kind of wrong argument would come with a segfault. so i guess mach_vm_read and mach_vm_write should be considered to wrap around

[not-matthias]

@iraizo Feel free to fork the repo and add the implementation for MacOS. You can take a look at the already existing implementations here.