mem: Fixed bug in Clear

mem/mem.go

@@ -75,7 +75,7 @@ func Clear(dst unsafe.Pointer, value byte, count uintptr) unsafe.Pointer {
 	b := (*byte)(dst)
 	for range count { // @todo: loop unroll/maybe use asm?
 		*b = value
-		b = (*byte)(unsafe.Add(dst, 1))
+		b = (*byte)(unsafe.Add(b, 1))
 	}
 	return dst
 }