ci(gcb): add libcxx build (#6253)

Author: devjgm

ci/cloudbuild/builds/libcxx.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+#
+# Copyright 2021 Google LLC
+#
+# 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.
+
+set -eu
+
+source "$(dirname "$0")/../../lib/init.sh"
+source module ci/cloudbuild/builds/lib/bazel.sh
+source module ci/cloudbuild/builds/lib/integration.sh
+
+export CC=clang
+export CXX=clang++
+
+mapfile -t args < <(bazel::common_args)
+args+=("--config=libcxx")
+bazel test "${args[@]}" --test_tag_filters=-integration-test ...
+
+mapfile -t integration_args < <(integration::args)
+integration::bazel_with_emulators test "${args[@]}" "${integration_args[@]}"

ci/cloudbuild/triggers/libcxx-ci.yaml

@@ -0,0 +1,12 @@
+filename: ci/cloudbuild/cloudbuild.yaml
+github:
+  name: google-cloud-cpp
+  owner: googleapis
+  push:
+    branch: ^master$
+name: libcxx-ci
+substitutions:
+  _BUILD_NAME: libcxx
+  _DISTRO: fedora
+tags:
+- ci

ci/cloudbuild/triggers/libcxx-pr.yaml

@@ -0,0 +1,13 @@
+filename: ci/cloudbuild/cloudbuild.yaml
+github:
+  name: google-cloud-cpp
+  owner: googleapis
+  pullRequest:
+    branch: ^master$
+    commentControl: COMMENTS_ENABLED_FOR_EXTERNAL_CONTRIBUTORS_ONLY
+name: libcxx-pr
+substitutions:
+  _BUILD_NAME: libcxx
+  _DISTRO: fedora
+tags:
+- pr