Tested using cross-compiling from linux:
zig build -Dcross=true -Dtarget=x86_64-windows nvim_bin
Note: not fully functional without a runtime, which still has to be
fuddled with manually
Macos and windows builds require a recent zig 0.15+dev version
As this zig master branch is currently too much in flux, we can't make
our CI depend on zig master.
Revisit CI after zig 0.15 release or at least feature freeze.