Fix some problems with sized deletion in libc++

[mclow.lists]

Summary

The sized deletion routines were recently added to libc++ (r229281). There are some problems with the current implementation. This fixes some of those problems, but there are others extant:

1. How we're going to support vendors who ship new dylibs infrequently; compatibility with existing dylibs. This is especially important if clang is going to implicitly generate calls to these routines.

2. The original commit had no tests.

[mclow.lists]

include/new

147

This change (and the one below) are two simple changes that the diff obscures:

1. Move the two variants that have a size_t param together.
2. Wrap them in an ifdef.

[mclow.lists]

This stuff has been superseded by LWG issue #2458

include/new

 ;
 _LIBCPP_NEW_DELETE_VIS void* operator new(std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _NOALIAS;
 _LIBCPP_NEW_DELETE_VIS void  operator delete(void* __p) _NOEXCEPT;
+_LIBCPP_NEW_DELETE_VIS void  operator delete(void* __p, const std::nothrow_t&) _NOEXCEPT;
+#ifdef _LIBCPP_BUILDING_NEW || _LIBCPP_STD_VER >= 14
 _LIBCPP_NEW_DELETE_VIS void  operator delete(void* __p, std::size_t __sz) _NOEXCEPT;
-_LIBCPP_NEW_DELETE_VIS void  operator delete(void* __p, const std::nothrow_t&) _NOEXCEPT;
 _LIBCPP_NEW_DELETE_VIS void  operator delete(void* __p, std::size_t __sz, const std::nothrow_t&) _NOEXCEPT;
+#endif
 
 _LIBCPP_NEW_DELETE_VIS void* operator new[](std::size_t __sz)
 #if !__has_feature(cxx_noexcept)

 ;
 _LIBCPP_NEW_DELETE_VIS void* operator new[](std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _NOALIAS;
 _LIBCPP_NEW_DELETE_VIS void  operator delete[](void* __p) _NOEXCEPT;
+_LIBCPP_NEW_DELETE_VIS void  operator delete[](void* __p, const std::nothrow_t&) _NOEXCEPT;
+#ifdef _LIBCPP_BUILDING_NEW || _LIBCPP_STD_VER >= 14
 _LIBCPP_NEW_DELETE_VIS void  operator delete[](void* __p, std::size_t __sz) _NOEXCEPT;
-_LIBCPP_NEW_DELETE_VIS void  operator delete[](void* __p, const std::nothrow_t&) _NOEXCEPT;
 _LIBCPP_NEW_DELETE_VIS void  operator delete[](void* __p, std::size_t __sz, const std::nothrow_t&) _NOEXCEPT;
+#endif
 
 inline _LIBCPP_INLINE_VISIBILITY void* operator new  (std::size_t, void* __p) _NOEXCEPT {return __p;}
 inline _LIBCPP_INLINE_VISIBILITY void* operator new[](std::size_t, void* __p) _NOEXCEPT {return __p;}

src/new.cpp

 
 _LIBCPP_WEAK _LIBCPP_NEW_DELETE_VIS
 void
-operator delete(void* ptr, size_t, const std::nothrow_t&) _NOEXCEPT
+operator delete(void* ptr, size_t, const std::nothrow_t& nt) _NOEXCEPT
 {
-    ::operator delete(ptr);
+    ::operator delete(ptr, nt);
 }
 
 _LIBCPP_WEAK _LIBCPP_NEW_DELETE_VIS

 
 _LIBCPP_WEAK _LIBCPP_NEW_DELETE_VIS
 void
-operator delete[] (void* ptr, size_t, const std::nothrow_t&) _NOEXCEPT
+operator delete[] (void* ptr, size_t, const std::nothrow_t& nt) _NOEXCEPT
 {
-    ::operator delete[](ptr);
+    ::operator delete[](ptr, nt);
 }
 
 #endif // !__GLIBCXX__