roll: third_party/pigweed 3 commits

f438978ee6805ca pw_tokenizer: Use uint64_t for calculation
f85d4f62a404caa pw_chrono: Add VirtualClock
dc92fa94360e3b8 pw_toolchain: Explicitly link with lld when using

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 8512b20c7f93492..f438978ee6805ca
Roller-URL: https://ci.chromium.org/b/8737778572277073089
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Icf93a6b354abb4f26b29d540547cbd0c8333ee34
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/233692
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.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 8512b20..f438978 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 8512b20c7f9349244b7d9340742d28ebd299e766
+Subproject commit f438978ee6805ca50835377581c78b8fe7a8c96e