Toward generic atomic operations

Also note that the atomics are just a part of the memory model. Using libatomic-ops, for example, does not guarantee that your compiler actually adheres to the memory model (e.g., does not introduce speculative stores that could be data races in a multi-threaded execution). There are different opinions about whether the C++11/C11 memory model should be the default even for non C++11/C11 compilations. IMO, this would be A Good Thing; other people are worried about potential performance disadvantages for single-threaded programs.