Switch GN defs on Mac and iOS to use frameworks instead of libs.

GN will be removing support for frameworks in the libs variable, so
might as well get ahead of it.

Change-Id: I67b118457721975ac2408308438d71172be66592
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/300181
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
2 files changed