roll: third_party/pigweed efc8002..c34cb4e (3 commits)

c34cb4e:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/319817 pw_toolchain: Workaround for missing builtins
ffda917:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/320922 pw_async2: Reword codelab waker instructions
d29fcf1:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/319819 pw_async2: Update docs

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: efc800231b225b..c34cb4ead63acf
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8704055625480252529
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I333292d90e698a61da3e1e8ed1492329c9a0b431
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/321128
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index efc8002..c34cb4e 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit efc800231b225b94b53ac73a67eeae9dd19d366d
+Subproject commit c34cb4ead63acf2198ecc52d95551700dcca8e67