Use the __DECONST macro rather than hand rolling the same thing.

Sponsored by:	DARPA, AFRL

lib/libc/stdlib/lsearch.c

@@ -39,11 +39,7 @@ lwork(const void *key, const void *base, size_t *nelp, size_t width,
 {
 	uint8_t *ep, *endp;
 
-	/*
-	 * Cast to an integer value first to avoid the warning for removing
-	 * 'const' via a cast.
-	 */
-	ep = (uint8_t *)(uintptr_t)base;
+	ep = __DECONST(uint8_t *, base);
 	for (endp = (uint8_t *)(ep + width * *nelp); ep < endp; ep += width) {
 		if (compar(key, ep) == 0)
 			return (ep);