standards/50889: NULL defined as 0 instead of (void *)0

[M. Warner Losh]

I have a #define in my tree that I switch back and forth from time to
time:

#if defined(_cplusplus) || !defined(_NULL_VOID)
#define NULL 0L
#else
#define NULL (void *) 0
#endif

and I add -D_NULL_VOID to build when I want to detect problems that
(void *) 0 detects, then switch it back to 0 for the problems that
that detects.

You can't win here.  I'd be inclined to leave things as the status quo.

Warner