[infra] Add comment regarding skcms use of mac_toolchain.

No-Try: true
Change-Id: I9ca13921cdc5ed388b6b4ba46d99a2d4e4735158
Reviewed-on: https://skia-review.googlesource.com/146532
Commit-Queue: Eric Boren <borenet@google.com>
Auto-Submit: Ben Wagner <benjaminwagner@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
1 file changed