Fix redefined-macro warning on non-UNIX platforms.

Change-Id: Ib22d104212f5b728938a87baae43c4a0884bf6ff
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/449358
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Julia Lavrova <jlavrova@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
4 files changed