title: Disable "deletion of copy constructor when move constructor is avaliable" on Clang
body: <p>Looking here on StackOverflow I found out that on Clang++ when using C++11 standard, if you have defined a move constructor to your class, the implicit constructor generation is disabled, i.e. copy constructor is "explicted deleted".</p>
  
  <p>Is there any way to disable this behavior?</p>
  
  <p>Also, is this behavior standardized? Because I don't have the same behavior in GCC.</p>