Function dtHashRef

Source/ThirdParty/recastnavigation/DetourNode.cpp:27–36

From Thomas Wang, https://gist.github.com/badboy/6267743

#ifdef DT_POLYREF64
// From Thomas Wang, https://gist.github.com/badboy/6267743
inline unsigned int dtHashRef(dtPolyRef a)
{
	a = (~a) + (a << 18); // a = (a << 18) - a - 1;
	a = a ^ (a >> 31);
	a = a * 21; // a = (a + (a << 2)) + (a << 4);
	a = a ^ (a >> 11);
	a = a + (a << 6);
	a = a ^ (a >> 22);
	return (unsigned int)a;
}
#else
inline unsigned int dtHashRef(dtPolyRef a)
{