Fluidsynth 2.2 upgrade, only download awesfx for Unix targets

[nikitalita]

This upgrades the headers and included Windows x86-64 libraries for fluidsynth to version 2.2. This resolves errors building on Windows as the current jorgan-fluidsynth library targets newer versions of fluidsynth.

This also prevents downloading and untarring the awesfx library on non-unix targets, as it's not built with other targets. This previously caused errors with building on Windows due to it including bsdtar instead of gnutar and the untarring step would fail.

[nikitalita]

Unfortunately, I notice there are some issues with the binaries that I built for AMD64 Windows, their dependencies are not loading; How were the fluidsynth dlls and their dependencies built before? I looked back at the git history and it doesn't seem to say.

[nikitalita]

I fixed it, but I had to add several additional libraries as dependencies which is not ideal; if you know how this was compiled before, please let me know so I can update this.

[svenmeier]

I didn't build fluidsynth for ages, iirc Graham did the latest updates.

Have you tried fluidsynth's binary release?

https://github.com/FluidSynth/fluidsynth/releases/tag/v2.2.1

Indeed it seems fluidsynth is requiring more dependencies now.

[nikitalita]

Ok, I updated the windows x86 and x86_64 binaries and the macos binaries to 2.2.1. This should be good to go now.