[Bug libstdc++/108391] '::operator delete(void*, size_t)' was not found when clang compiled libstdc++

[jincikang at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108391

--- Comment #3 from jinci kang <jincikang at gmail dot com> ---
(In reply to Jonathan Wakely from comment #2)
> Oh clang isn't using it, you're using it explicitly. So then that's a bug in
> your code. You shouldn't use it unless the macro is defined to say that it's
> usable.

So what do you think I should do?
```cpp
#ifdef __clang__
#define __cpp_sized_deallocation
#endif

#include <new>

int main() {
  void* p = ::operator new[](2);
  ::operator delete[](p, 2);
}
```
I think this is a bit troublesome, this API can be used directly after C++14.