I made a comment, but feel free to merge this. We can improve the performance later, specially because now there's no windows support at all.

Changed the fix according to the suggestion to use String.build instead of string interpolation.

I guess that could happen... ¯_(ツ)_/¯

@Vexatos I meant using String.build instead of string.gsub. Something like:

String.build do |io|
  name.each_char do |char|
    case char
      ...
    end
  end
end

Ah, yeah, sorry, that would probably be a lot faster than gsub.

Also not mangling _ now since that is a fairly common character that does not need to be mangled.

Do we need to mangle specifically for Windows anymore?

I just tried without the special mangling for Windows and the object file ends up being invalid (when executing the cl command on Windows)

Can we get this cherry-picked for 0.24.2? Would be a great help for the ongoing windows efforts. @bcardiff