[third_party/pigweed] Roll 4 commits

51572a37f0c380b pw_env_setup: Update default sysroot version
e0492ee7eaed1f4 roll: clang
73d4ddb4cb33de4 pw_allocator: Add missing return statement
a1faba5d2d569a1 SEED-0129: Claim SEED number

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: ccc5241d8133cd2..51572a37f0c380b
Roller-URL: https://ci.chromium.org/b/8749297084576321905
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I24ae781fb7fc5468d6e838b07010cebf4efc6d6d
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/quickstart/bazel/+/207290
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: 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 ccc5241..51572a3 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit ccc5241d8133cd25bb02c7b4dd48a640ccea8508
+Subproject commit 51572a37f0c380ba3d6cc618dcf462bbb4458048