C++20 / gcc 10 fix: remove allocator::destroy call
C++20 / gcc 10 fix: remove allocator::destroy call

std::allocator::destroy was deprecated in C++17 and removed in C++20 (https://en.cppreference.com/w/cpp/memory/allocator/destroy).
Its replacement std::allocator_traits<T>::destroy was introduced in C++11 (https://en.cppreference.com/w/cpp/memory/allocator_traits/destroy).
This conditionally compiled fix enables code to compile with gcc 10+ or any new C++20-compliant compiler.
nvmd/libkdtree,nvmd/libkdtree,nvmd/libkdtree