add meson build files

[bl4ckb0ne]

I'm experiencing issues cross compiling with autotools, I can't find a way to generate viv_interpose.so, only .la files.

So here's a modern build system.

[laanwj]

Thank you! This is much better, i'm unable to test it right now but will do so when i can.

[bl4ckb0ne]

Do you also want a commit to remove the autotools files?

I'm also not sure about the license, there's none in the repo but https://github.com/etnaviv/etna_viv is MIT so I figured it would be the same.