[libc++] Trigger both Clang and libc++ CI when there are changes to both

[ldionne]

Summary

Per post-commit comments in https://reviews.llvm.org/D137759.

[Mordante]

Sorry I overlooked this review. Based on the CI output it only runs the Clang CI right.

[ldionne]

This will be superseded by D155078.

libcxx/utils/ci/buildkite-pipeline-clang.yml

agents:
       queue: "libcxx-builders"
       os: "linux"
     retry:
       automatic:
         - exit_status: -1  # Agent was lost
           limit: 2
     timeout_in_minutes: 120
 
-  - label: "Modules"
+  - label: "Clang Modules"
     commands:
       - "buildkite-agent artifact download 'install/**' ."
       - "export CC=$(pwd)/install/bin/clang"
       - "export CXX=$(pwd)/install/bin/clang++"
       - "chmod +x install/bin/clang install/bin/clang++"
       - "libcxx/utils/ci/run-buildbot generic-modules"
     artifact_paths:
       - "**/test-results.xml"

libcxx/utils/ci/generate-buildkite-pipeline

 #!/usr/bin/env bash
 #===----------------------------------------------------------------------===##
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #
 #===----------------------------------------------------------------------===##
 
 #
 # This script generates the appropriate libc++ CI pipeline based on which project(s) were changed.
 #
 
 if git diff --name-only HEAD~1 | grep -q -E "^libcxx/|^libcxxabi/|^libunwind/|^runtimes/|^cmake/"; then
-  LIBCXX_CHANGED=true
+  cat libcxx/utils/ci/buildkite-pipeline.yml
 fi
 
 if git diff --name-only HEAD~1 | grep -q -E "^clang/"; then
-  CLANG_CHANGED=true
-fi
-
-if [[ "${CLANG_CHANGED}" == "true" && "${LIBCXX_CHANGED}" != "true" ]]; then
   cat libcxx/utils/ci/buildkite-pipeline-clang.yml
-else
-  cat libcxx/utils/ci/buildkite-pipeline.yml
 fi