818f886f1d
- Adds a flag `-a` for specifying the architecture (only works for MacOS at the moment). - Calls '-uname -m' when no architecture is specified on MacOS. - uname values from: https://en.wikipedia.org/wiki/Uname Change-Id: Id5eb530e6571d2de452acd90d3b0d7e24fb32747 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/239468 Reviewed-by: Nicholas Shahan <nshahan@google.com> Commit-Queue: Mark Zhou <markzipan@google.com>