Bazel support is through utils/bazel, and the BUILD files in `benchmark`
just complicate downstream integrates for bazel based builds.
Differential Revision: https://reviews.llvm.org/D115733
Pulled the latest (b000672), which adds an option to disable -Werror,
which caused issues previously (see for instance
https://reviews.llvm.org/D112012)
Applied https://github.com/google/benchmark/pull/1305 to unblock, as
this issue is causing downstream buildbot failures.
The only change is in llvm/CMakeLists.txt, where we set
BENCHMARK_ENABLE_WERROR to have the same value as LLVM_ENABLE_WERROR.
This patch also introduces a convenience script to pull benchmark from
upstream.
Differential Revision: https://reviews.llvm.org/D115684
