[libc++] Add CI job testing on OpenBSD

Author: brad0

libcxx/include/__algorithm/simd_utils.h

@@ -28,7 +28,7 @@ _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 // TODO: Find out how altivec changes things and allow vectorizations there too.
-#if _LIBCPP_STD_VER >= 14 && defined(_LIBCPP_CLANG_VER) && !defined(__ALTIVEC__)
+#if _LIBCPP_STD_VER >= 14 && defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 1700 && !defined(__ALTIVEC__)
 #  define _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS 1
 #else
 #  define _LIBCPP_HAS_ALGORITHM_VECTOR_UTILS 0

libcxx/include/__configuration/compiler.h

@@ -33,8 +33,8 @@
 // Warn if a compiler version is used that is not supported anymore
 // LLVM RELEASE Update the minimum compiler versions
 #  if defined(_LIBCPP_CLANG_VER)
-#    if _LIBCPP_CLANG_VER < 1700
-#      warning "Libc++ only supports Clang 17 and later"
+#    if _LIBCPP_CLANG_VER < 1600
+#      warning "Libc++ only supports Clang 16 and later"
 #    endif
 #  elif defined(_LIBCPP_APPLE_CLANG_VER)
 #    if _LIBCPP_APPLE_CLANG_VER < 1500

libcxx/utils/ci/buildkite-pipeline.yml

@@ -173,6 +173,19 @@ steps:
       os: freebsd
     <<: *common
 
+
+- group: ':openbsd: OpenBSD'
+  steps:
+  - label: OpenBSD -current amd64
+    command: libcxx/utils/ci/run-buildbot generic-cxx23
+    env:
+      CC: clang
+      CXX: clang++
+    agents:
+      queue: libcxx-builders
+      os: openbsd
+    <<: *common
+
 - group: ':android: Android'
   steps:
   - label: Android 5.0, x86 NDK