[runtimes] Add TODO about CXX_STANDARD_REQUIRED being off after review comment

Author: ldionne

libcxx/CMakeLists.txt

@@ -507,7 +507,7 @@ function(cxx_add_basic_build_flags target)
   # Use C++23 for all targets.
   set_target_properties(${target} PROPERTIES
     CXX_STANDARD 23
-    CXX_STANDARD_REQUIRED OFF
+    CXX_STANDARD_REQUIRED OFF # TODO: Make this REQUIRED once we don't need to accommodate the LLVM documentation builders using an ancient CMake
     CXX_EXTENSIONS NO)
 
   # When building the dylib, don't warn for unavailable aligned allocation

libcxxabi/src/CMakeLists.txt

@@ -172,7 +172,7 @@ set_target_properties(cxxabi_shared_objects
   PROPERTIES
     CXX_EXTENSIONS OFF
     CXX_STANDARD 23
-    CXX_STANDARD_REQUIRED OFF
+    CXX_STANDARD_REQUIRED OFF # TODO: Make this REQUIRED once we don't need to accommodate the LLVM documentation builders using an ancient CMake
     COMPILE_FLAGS "${LIBCXXABI_COMPILE_FLAGS}"
     DEFINE_SYMBOL ""
 )
@@ -252,7 +252,7 @@ set_target_properties(cxxabi_static_objects
   PROPERTIES
     CXX_EXTENSIONS OFF
     CXX_STANDARD 23
-    CXX_STANDARD_REQUIRED OFF
+    CXX_STANDARD_REQUIRED OFF # TODO: Make this REQUIRED once we don't need to accommodate the LLVM documentation builders using an ancient CMake
     COMPILE_FLAGS "${LIBCXXABI_COMPILE_FLAGS}"
 )