appveyor: try using vcvarsall
appveyor: try using vcvarsall

zig-lang/zig,andrewrk/zig,Dimenus/zig,raulgrell/zig,zig-lang/zig,raulgrell/zig,Dimenus/zig,raulgrell/zig,andrewrk/zig,raulgrell/zig,Dimenus/zig,raulgrell/zig,zig-lang/zig