[roll third_party/pigweed] pw_build: Disable CGo on MacOS

This tells the Go compiler to build without the C standard library on
MacOS due to issues with include paths in certain environments.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/45443

third_party/pigweed Rolled-Commits: 10663e21d624bda..6ea2df408753c02
Roller-URL: https://ci.chromium.org/b/8847219065681924784
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8847219065681924784
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I25c37cccb882ddf639fb947cd1c4894156866ddb
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/45481
Reviewed-by: 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 10663e2..6ea2df4 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 10663e21d624bda5c7b66ba0147fb911f45b0eef
+Subproject commit 6ea2df408753c028a04630255da12314686c835d