Actually fix missing symbols on Linux build for real this time

[iamgreaser]

This also reorganises Makefile.srcs so it's easier to tweak.

Apparently, there are more files I needed to compile and link. Otherwise, the library can work one day, and complain about a missing symbol the next.

If this breaks again, I will do an exhaustive search to make sure every symbol links and do another PR for that.

[Frooxius]

Ah thank you! It's really odd that it's being so moody, with it being statically compiled. I'll merge this in and we'll see how it works!