[roll third_party/pigweed] pw_toolchain: Use -Wpedantic in Clang CMake builds

Also migrate from plain add_library to pw_add_library.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/110972

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 064aecc4c15ae4d..eb3a6295df0bc14
Roller-URL: https://ci.chromium.org/b/8801935737206658177
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Id0490891fea0c63f6263ab2ec680191fd0cad0ed
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/112050
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 064aecc..eb3a629 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 064aecc4c15ae4dd71570cdd7af84aa9c2ba65bf
+Subproject commit eb3a6295df0bc140ea7cb5df27f89df2c0d0d2d9