stdlib.h needed for size_t

[Tam Toucan]

Been meaning to post this for a while. I have to add a
#include <stdlib.h>
to chipmunk_types.h so that size_t is define'd.

[slembcke]

That one has been silently bothering me for a while too. I think I came up with a decent workaround though.

The reason that was set to size_t in the first place was for 64bit compatibility. You get nasty warnings about casting pointers to integers of different sizes. Using size_t was the closest thing that I could find to a portable guarantee that it was an int size that was as big as the pointer size. Now, as these were all being used for hash values, so I didn't really care about the extra bits just that it was a mostly unique value. It seems that there are only 2 places where pointers were used directly as hash values in the Chipmunk code. Getting a hash value for a shape pair, and for post step callbacks.

I changed the hash value type back to unsigned int and added double casts when I need to convert a pointer to a hash value. That seems to work without complaint and does what I want it to do. I also added a 64bit build to my default OSX build so I should be able to catch 64bit issues more quickly.