Introduce the nullptr constant
Abstract
Since more than a decade C++ has already replaced the problematic definition of NULL which might be either of integer type or void*. By using a new constant nullptr, they achieve a more constrained specification, that allows much better diagnosis of user code. We propose to integrate this concept into C as far as possible without putting much strain on implementations. This is a split-off of N2368 that builds on the approval of the "keywords" patches.