commit bd497c98b5f3793a605e150739385525cc35891a
author David 'Digit' Turner <digit@google.com> Tue Jan 26 23:10:26 2021 +0000
committer CQ Bot <commit-bot@chromium.org> Tue Jan 26 23:10:26 2021 +0000
tree 3b53ea0dab06c8dd8c98b2ea942ab43f5af98e43
parent 15bc81c379734ddd452a2aed1a314ab62c7e8a40

[build] Add library_headers() template.

This CL introduces a new template used to declare the public headers of
a given C++ library. As documented with the template, this provides
opportunity for higher parallelism, when targets only need to include
headers to get type definitions, and not link to the corresponding
library.

This also demonstrate how a few zx_library() instances are changed to
use the new template, i.e.:

- src/connectivity/openthread/lib/ot-radio/BUILD.gn:
  src/connectivity/openthread/lib/ot-stack/BUILD.gn:
  Turn a source-less zx_library() instance  directly into a
  library_headers() instance directly.

  This should be possible for any zx_library() instance that is not
  published to the SDK, and doesn't have any sources.

- simple-audio-stream: turn the zx_library() into a source_set() with
  a corresponding library_headers() target. This generakky

- src/lib/ddk: Move the public headers of a given zx_library() into
  its own library_headers() instance. The difference is that the headers
  will now participate in GN inclusion checks during 'gn gen', something
  that zx_library() cannot do without breaking kernel compilation (but
  this target is not compiled for the kernel).

  Also turns a few zx_library() source-less instances into a
  corresponding library_headers() instance.

Bug: None
Change-Id: I223b9b689623ac35de55b6768b803c2e71fc288f
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/474231
Fuchsia-Auto-Submit: David Turner <digit@google.com>
Commit-Queue: David Turner <digit@google.com>
Reviewed-by: P.Y. Laligand <pylaligand@google.com>