This extends the pattern in freetype2 to expat, icu, libjpeg-turbo, libpng, libwebp, and zlib, and gives all these an arg to control which to use.
Homebrew doesn't have dng_sdk, piex, or sftnly, or I'd have done the same for them too.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4260
DOCS_PREVIEW= https://skia.org/?cl=4260
Change-Id: I82e780502bf2217336e791787f172a6fc8f55460
Reviewed-on: https://skia-review.googlesource.com/4260
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Hal Canary <halcanary@google.com>
We might as well match the folks who are using our GN files now.
We've got plenty of strategies in our pocket for when we try to move Chrome
onto our GN files (and who knows, there may be even a new better way by then):
* Same sort of rename in Chrome's third_party
* Aliased targets via //build/secondary in Chrome.
* Indirection via build_overrides
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2265503002
Review-Url: https://codereview.chromium.org/2265503002
