[libc++][ci] Keep the C++03 build job on Clang 12

Because of https://reviews.llvm.org/D104500, libc++ is broken with
recent Clangs in C++03 mode.

diff --git a/libcxx/utils/ci/run-buildbot b/libcxx/utils/ci/run-buildbot
index c2feb07..c401f22 100755 (executable)
--- a/libcxx/utils/ci/run-buildbot
+++ b/libcxx/utils/ci/run-buildbot
@@ -180,6 +180,9 @@ check-generated-output)
     python3 libcxx/utils/graph_header_deps.py >/dev/null
 ;;
 generic-cxx03)
+    # TODO: Switch to compiling with Clang ToT once issues with https://reviews.llvm.org/D104500 are resolved.
+    export CC=clang-12
+    export CXX=clang++-12
     clean
     generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-cxx03.cmake" \
                    -DLIBCXX_TEST_CONFIG="${MONOREPO_ROOT}/libcxx/test/configs/libcxx-trunk-shared.cfg.in"