Blender Git Loki

Fix for a *very* nasty bug... somewhere in the ancient past - I tracked it
back to 1.4 - comparing pointers apparently gave warnings or errors... I
don't really have a memory of that. Could be the Irix compiler.

What it was used for is sorting edges in arrays or hash lists, like:

if( ((long)v1) > ((long)v2) )

long is defined to be pointer size, so that should work 32/64 bits, where
it not that the long cast makes the value SIGNED! :)

Ken Hughes discovered this... noting that when his system uses a calloc, the
returned pointer had an uncommon address making the long negative.
It was a very hard bug to track, since (apparently) most OS's have an address
space being still in the lower part of an long...

Anyhoo; I have removed a couple of (long) casts from pointer comparing now,
need to get compile feedback if that's compliant for all our OS's.
If so, quite a lot of such hacks have to be removed from our code, or make
them casting to an unsigned long...

This has been confirmed to fix bugs #2709 and #2710. Thanks Ken!