Remove compatibility with Cemuhook and fix exports

[Crementif]

Fixes #31.

Also switches to an in-line way of exporting symbols.

[ArtemisX64]

I was planning on doing something similar. But cool

[Tachi107]

__declspec(dllexport)'s GCC equivalent is __attribute__ ((visibility ("default"))), but I don't know if it is relevant here.

Edit: see https://github.com/Tachi107/cloudflare-ddns/blob/a3a8fd14b367645e81fc9e703150536ca459c681/include/ddns/cloudflare-ddns.h#L45-L72

[ghost]

Cemuhook is pretty much no longer needed for Cemu, so that's a good sign that Cemuhook is getting abandoned.

[Exzap]

Looks good.
End of an era. RIP Cemuhook

[Crementif]

__declspec(dllexport)'s GCC equivalent is __attribute__ ((visibility ("default"))), but I don't know if it is relevant here.

Yeah, I'll make a commit changing the DLLEXPORT tomorrow with that, even if there's no need for those kinda functions to be exposed on Linux yet.