Merge pull request swiftlang#42350 from compnerd/placement

Runtime: correct invalid C++ workaround

Author: compnerd

include/swift/Runtime/Atomic.h

@@ -95,14 +95,6 @@ struct aligned_alloc<Alignment_, true> {
     free(ptr);
 #endif
   }
-
-#if defined(_WIN32)
-  // FIXME: why is this even needed?  This is not permitted as per the C++
-  // standrd new.delete.placement (§17.6.3.4).
-  [[nodiscard]] void *operator new(std::size_t size, void *where) noexcept {
-    return ::operator new(size, where);
-  }
-#endif
 };
 
 /// The default implementation for swift::atomic<T>, which just wraps

stdlib/public/runtime/MetadataImpl.h

@@ -51,6 +51,7 @@
 #include "EnumImpl.h"
 
 #include <cstring>
+#include <new>
 #include <type_traits>
 
 namespace swift {