[PATCH] eal/x86: fix build on systems with WAITPKG support

[Bruce Richardson]

On Mon, Aug 28, 2023 at 12:42:38PM +0200, Stephen Hemminger wrote:
>    For humor
>    #define RTE_CASTAWAY(x) ((void *)(uinptr_t)(x))

Yes, actually thought about that. Was also wondering about making it an
inline function rather than macro, to ensure its only used on pointers, and
to make clear what is being cast away:

static inline void *
rte_cast_no_volatile(volatile void *x)
{
	return (void *)(uintptr_t)(x);
}

and similarly we could do a rte_cast_no_const(const void *x).

WDYT?

/Bruce