message: Add MacOS explaination to building guide.
diff: @@ -81,6 +81,13 @@ Should just build. We recommend using the MSVC toolchain whenever possible, the
  Just copy-paste the exe and resource directory to the destination computer.
  +# MacOS/iOS
  +
  +At the moment we unfortunately cannot provide support for developing on
  +mac (none of the developers have hardware). While `ggez` tries not to do
  +anything that would make it *not* work on Mac, it is a DIY target. If
  +you resolve this issue feel free to open a PR.
  +
  # Android
  Not officially supported yet. ;_; See https://github.com/ggez/ggez/issues/70
  