AFAICT, only gm/etc1 uses third_party/etc1

The need for -Ithird_party/gif has already been
rewritten away, and we can do the same for etc1.

Change-Id: I97408652682b5ec406647108056e7a1ea6a56c29
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/210131
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
5 files changed