create global symlink to Mac SDK during bazel toochain config

Bug: https://bugs.chromium.org/p/skia/issues/detail?id=14016
Change-Id: I9a145141ebb0323011fd77f3433436a8bffcae37
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/628057
Commit-Queue: Jorge Betancourt <jmbetancourt@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
3 files changed