[libc++][CI] Switches to clang-format-16.

[Mordante]

Summary

Uses an absolute path to the selected binary.
Updates the formatting of two files to match clang-format-16 style.

Depends on D144126

[philnik]

Thanks! LGTM.

libcxx/include/__expected/unexpected.h

static_assert(__valid_std_unexpected<_Err>::value,
                 "[expected.un.general] states a program that instantiates std::unexpected for a non-object type, an "
                 "array type, a specialization of unexpected, or a cv-qualified type is ill-formed.");
 
 public:
   _LIBCPP_HIDE_FROM_ABI constexpr unexpected(const unexpected&) = default;
   _LIBCPP_HIDE_FROM_ABI constexpr unexpected(unexpected&&)      = default;
 
   template <class _Error = _Err>
-    requires(!is_same_v<remove_cvref_t<_Error>, unexpected> && //
-             !is_same_v<remove_cvref_t<_Error>, in_place_t> && //
+    requires(!is_same_v<remove_cvref_t<_Error>, unexpected> &&          //
+             !is_same_v<remove_cvref_t<_Error>, in_place_t> &&          //
              is_constructible_v<_Err, _Error>)
   _LIBCPP_HIDE_FROM_ABI constexpr explicit unexpected(_Error&& __error) //
       noexcept(is_nothrow_constructible_v<_Err, _Error>)                // strengthened
       : __unex_(std::forward<_Error>(__error)) {}
 
   template <class... _Args>
     requires is_constructible_v<_Err, _Args...>
   _LIBCPP_HIDE_FROM_ABI constexpr explicit unexpected(in_place_t, _Args&&... __args) //

libcxx/src/memory_resource.cpp

#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
   }
 #elif !defined(_LIBCPP_HAS_NO_THREADS)
   static constinit memory_resource* res = &res_init.resources.new_delete_res;
   static mutex res_lock;
   if (set) {
     new_res = new_res ? new_res : new_delete_resource();
     lock_guard<mutex> guard(res_lock);
     memory_resource* old_res = res;
-    res = new_res;
+    res                      = new_res;
     return old_res;
   } else {
     lock_guard<mutex> guard(res_lock);
     return res;
   }
 #else
   static constinit memory_resource* res = &res_init.resources.new_delete_res;
   if (set) {

libcxx/utils/ci/buildkite-pipeline.yml

steps:
   - label: "Generated output"
     command: "libcxx/utils/ci/run-buildbot check-generated-output"
     artifact_paths:
       - "**/generated_output.patch"
       - "**/generated_output.status"
     env:
         CC: "clang-${LLVM_HEAD_VERSION}"
         CXX: "clang++-${LLVM_HEAD_VERSION}"
-        # TODO ENABLE
-        # CLANG_FORMAT: "/usr/bin/clang-format-${LLVM_STABLE_VERSION}"
-        CLANG_FORMAT: "clang-format-15"
+        CLANG_FORMAT: "/usr/bin/clang-format-${LLVM_STABLE_VERSION}"
     agents:
       queue: "libcxx-builders"
       os: "linux"
     retry:
       automatic:
         - exit_status: -1  # Agent was lost
           limit: 2
     timeout_in_minutes: 120

libcxx/utils/data/ignore_format.txt

 libcxx/include/__chrono/file_clock.h
 libcxx/include/__chrono/formatter.h
 libcxx/include/__chrono/hh_mm_ss.h
 libcxx/include/__chrono/high_resolution_clock.h
 libcxx/include/__chrono/literals.h
 libcxx/include/__chrono/monthday.h
 libcxx/include/__chrono/month.h
 libcxx/include/__chrono/month_weekday.h
-libcxx/include/__chrono/statically_widen.h
 libcxx/include/__chrono/steady_clock.h
 libcxx/include/__chrono/system_clock.h
 libcxx/include/__chrono/time_point.h
 libcxx/include/__chrono/weekday.h
 libcxx/include/__chrono/year.h
 libcxx/include/__chrono/year_month_day.h
 libcxx/include/__chrono/year_month.h
 libcxx/include/__chrono/year_month_weekday.h