Merge topic 'clang_c23' into release-3.27

65288eb9 Clang: use -std=c23 for Clang 18+

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: scivision <michael@scivision.dev>
Merge-request: !8716

Modules/Compiler/Clang-C.cmake

@@ -48,7 +48,10 @@ if("x${CMAKE_C_COMPILER_FRONTEND_VARIANT}" STREQUAL "xGNU")
     set(CMAKE_C17_EXTENSION_COMPILE_OPTION "-std=gnu17")
   endif()
 
-  if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 9.0)
+  if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 18.0)
+    set(CMAKE_C23_STANDARD_COMPILE_OPTION "-std=c23")
+    set(CMAKE_C23_EXTENSION_COMPILE_OPTION "-std=gnu23")
+  elseif(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 9.0)
     set(CMAKE_C23_STANDARD_COMPILE_OPTION "-std=c2x")
     set(CMAKE_C23_EXTENSION_COMPILE_OPTION "-std=gnu2x")
   endif()