> | > I would like to add:
> | > 
> | >     /* No intptr_t dependency here */
> | >     #define __UNCONST(a) ((void *)(unsigned long)(const void *)(a))
> | > 
> | > in <sys/cdefs.h>
> | > 
> | > Any objections?
> | 
> | FreeBSD has __DECONST.
> | please follow it unless there's a compelling reason.
> 
> Ok, DECONST it is...

i think that it's a bad idea to follow only its name while being imcompatible.
FreeBSD's is:
#define	__DECONST(type, var)	((type)(uintptr_t)(const void *)(var))

YAMAMOTO Takashi