Enigma 1.30-beta on macOS Big Sur ready for testing

[Sidney Markowitz]

I've uploaded a dmg file that should be tried out, built under Big Sur 
with the 1.30 beta.

https://github.com/Enigma-Game/Enigma/releases/download/1.30-beta/Enigma-1.30-beta-Big-Sur.dmg

It was built and tested only on Big Sur, so I have no idea if it will 
run on Mojave or Catalina. Feel free to give it a go, but don't expect 
much. Once this is merged into the master branch I'll set about 
producing a build on Mojave which hopefully will allow for one 
distribution dmg that runs on all three OS versions.

This was built from the "macbuild" branch on our Github repo.

This is now ready to merge to master. Andreas, should I go ahead with 
the merge? Once it is in master, then installing from Homebrew can be 
made to work without any local editing of the formula.

The branch also contains some changes to the build files that I found 
were needed to get 1.30-beta to build on a Windows machine in the msys2 
environment using mingw32.

The good news regarding a win32 build is that in an msys2 build 
environment for mingw32 with required packages installed, this will 
build from the distribution sources using a simple

 configure --with-system-enet --prefix=somethingconvenient
 make
 make install

This links quite a bit more statically and requires fewer DLLs in the 
distribution, so I really am quite mystified about how the zip that was 
uploaded was built.

Regards,

 Sidney