Add a builder for making progress on hermetic toolchain on main branch (

#4576)

b/371241293

.github/config/linux-evergreen.json

@@ -0,0 +1,15 @@
+{
+  "docker_service": "linux",
+  "platforms": [
+    "linux-x64x11-evergreen"
+  ],
+  "targets": [
+    "base_unittests"
+  ],
+  "includes": [
+    {
+      "name": "x64",
+      "platform": "linux-x64x11-evergreen"
+    }
+  ]
+}

.github/workflows/linux.yaml

@@ -43,3 +43,14 @@ jobs:
       nightly: ${{ github.event.inputs.nightly }}
     secrets:
       datadog_api_key: ${{ secrets.DD_API_KEY }}
+  # This is cobalt on linux using evergreen build config
+  linux-evergreen:
+    uses: ./.github/workflows/main.yaml
+    permissions:
+      packages: write
+      pull-requests: write
+    with:
+      platform: linux-evergreen
+      nightly: ${{ github.event.inputs.nightly }}
+    secrets:
+      datadog_api_key: ${{ secrets.DD_API_KEY }}

cobalt/build/configs/linux-x64x11-evergreen/args.gn

@@ -0,0 +1,3 @@
+import("//cobalt/build/configs/linux-x64x11/args.gn")
+
+use_custom_libc = true

cobalt/build/configs/modular_variables.gni

@@ -0,0 +1,18 @@
+# Copyright 2024 The Cobalt Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+declare_args() {
+  # TODO: b/371241293 - Remove this variable when the hermetic toolchain is setup
+  use_custom_libc = false
+}

cobalt/build/gn.py

@@ -138,6 +138,7 @@ def main(out_directory: str, platform: str, build_type: str,
           'chromium_android-arm64',
           'chromium_android-x86',
           'linux-x64x11',
+          'linux-x64x11-evergreen',
           'android-arm',
           'android-arm64',
           'android-x86',