--- build/config/sanitizers/sanitizers.gni.orig	2026-09-30 02:11:56 UTC
+++ build/config/sanitizers/sanitizers.gni
@@ -543,14 +543,13 @@ template("ubsan_hardening") {
       cflags = [
         "-fsanitize=${invoker.sanitizer}",
         "-fsanitize-trap=${invoker.sanitizer}",
-
-        # Prevents `__has_feature(undefined_behavior_sanitizer)`
-        # from evaluating true. Configs defined here are intended to
-        # be usable even in release builds, i.e. as widely as possible.
-        # It's important not to have full-on UBSan workarounds activate
-        # just because we built support for a specific sanitizer.
-        "-fsanitize-ignore-for-ubsan-feature=${invoker.sanitizer}",
       ]
+      if (!is_bsd) {
+        # -fsanitize-ignore-for-ubsan-feature is a Chromium clang extension.
+        cflags += [
+          "-fsanitize-ignore-for-ubsan-feature=${invoker.sanitizer}",
+        ]
+      }
       if (defined(invoker.cflags)) {
         cflags += invoker.cflags
       }