Add //build_overrides/crubit.gni

Bug: None
Change-Id: I889d65c06a73512d7e8269a1711202429d4f7a5f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/490360
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Jeremy Leconte <jleconte@google.com>
Reviewed-by: Jeremy Leconte <jleconte@google.com>
Auto-Submit: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#48206}

build_overrides/crubit.gni

diff --git a/build_overrides/crubit.gni b/build_overrides/crubit.gni
new file mode 100644
index 0000000..dc9ecad
--- /dev/null
+++ b/build_overrides/crubit.gni
@@ -0,0 +1,14 @@
+# Copyright 2026 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+crubit_src_dir = "//third_party/rust-toolchain/lib/third_party/crubit"
+crubit_absl_dep_target = "//third_party/abseil-cpp:absl"
+crubit_gn_configs_to_remove = [
+  "//build/config/compiler:chromium_code",
+  "//build/config/compiler:disallow_unstable_features",
+]
+crubit_gn_support_configs_to_add = [
+  "//build/config/compiler:no_chromium_code",
+  "//build/rust/crubit:allow_unstable_features_required_by_crubit",
+]