[libcxx] Provide set_new_handler/get_new_handler on Windows

[phosek]

Summary

These are not provided by VCRuntime so we need to provide our own.

[philnik]

I don't understand. Do we never test the #else mode? Otherwise this should have been caught by the CI.

[phosek]

Superseded by D158450.

libcxx/include/new

class _LIBCPP_EXCEPTION_ABI bad_array_new_length
     : public bad_alloc
 {
 public:
     bad_array_new_length() _NOEXCEPT;
     ~bad_array_new_length() _NOEXCEPT override;
     const char* what() const _NOEXCEPT override;
 };
 
-typedef void (*new_handler)();
-_LIBCPP_FUNC_VIS new_handler set_new_handler(new_handler) _NOEXCEPT;
-_LIBCPP_FUNC_VIS new_handler get_new_handler() _NOEXCEPT;
-
 #elif defined(_HAS_EXCEPTIONS) && _HAS_EXCEPTIONS == 0 // !_LIBCPP_ABI_VCRUNTIME
 
 // When _HAS_EXCEPTIONS == 0, these complete definitions are needed,
 // since they would normally be provided in vcruntime_exception.h
 class bad_alloc : public exception {
 public:
   bad_alloc() noexcept : exception("bad allocation") {}
 
 private:
   friend class bad_array_new_length;
 
   bad_alloc(char const* const __message) noexcept : exception(__message) {}
 };
 
 class bad_array_new_length : public bad_alloc {
 public:
   bad_array_new_length() noexcept : bad_alloc("bad array new length") {}
 };
 #endif // defined(_LIBCPP_ABI_VCRUNTIME) && defined(_HAS_EXCEPTIONS) && _HAS_EXCEPTIONS == 0
 
+typedef void (*new_handler)();
+_LIBCPP_FUNC_VIS new_handler set_new_handler(new_handler) _NOEXCEPT;
+_LIBCPP_FUNC_VIS new_handler get_new_handler() _NOEXCEPT;
+
 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void __throw_bad_alloc();  // not in C++ spec
 
 _LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
 void __throw_bad_array_new_length()
 {
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
     throw bad_array_new_length();
 #else

libcxx/src/new.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include <__memory/aligned_alloc.h>
 #include <new>
 #include <stdlib.h>
 
 #include "include/atomic_support.h"
 
 #if defined(_LIBCPP_ABI_MICROSOFT)
-#   if !defined(_LIBCPP_ABI_VCRUNTIME)
-#       include "support/runtime/new_handler_fallback.ipp"
-#   endif
+#   include "support/runtime/new_handler_fallback.ipp"
 #elif defined(LIBCXX_BUILDING_LIBCXXABI)
 #   include <cxxabi.h>
 #elif defined(LIBCXXRT)
 #   include <cxxabi.h>
 #   include "support/runtime/new_handler_fallback.ipp"
 #elif defined(__GLIBCXX__)
     // nothing to do
 #else