[third_party/pigweed] Roll 2 commits

c4e9c62a8e6b36d pw_build: Make build warnings configurable in CMak
6b582970e1b81d2 pw_sync: Extend CMake support

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: e858b8187bc5730..c4e9c62a8e6b36d
Roller-URL: https://ci.chromium.org/b/8824490464915841201
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8824490464915841201
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I6edac85bc0d837e78157de37d309e3ee63c17192
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/80100
Bot-Commit: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index e858b81..c4e9c62 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit e858b8187bc57304ed564663aa8408abe903f577
+Subproject commit c4e9c62a8e6b36d0deac9fea6bfb85059bedadd0