[roll third_party/pigweed] roll: clang

From: git_revision:020d2fb7711d70e296f19d83565f8d93d2cfda71
To: git_revision:576b184d6e3b633f51b908b61ebd281d2ecbf66f
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/169370
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: f1192a73c6f201d..df79662e0626fd9
Roller-URL: https://ci.chromium.org/b/8770991971559796401
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ia85a66d270aa72b1d232e39dbc4c61ffccc598f0
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/169297
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index f1192a7..df79662 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit f1192a73c6f201d4473b05b09c42a33f38ec343c
+Subproject commit df79662e0626fd9d8d2609ccbd86d02e43df133a