Remove 'public' from disabled optional target.

An 'optional' target my wish to define public includes. When the target
is not enabled those public includes should not be present.

Change-Id: I1d0fc4553df100adf9178ad3f57bc0f5bb8f0fcb
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/294658
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
1 file changed