This is xnu-8019. See this file in:
/*
 * Copyright (c) 2006-2007 Apple Inc. All rights reserved.
 */

#ifndef _ARM__PARAM_H_
#define _ARM__PARAM_H_

#if defined (__arm__) || defined (__arm64__)

#include <arm/_types.h>

/*
 * Round p (pointer or byte index) up to a correctly-aligned value for all
 * data types (int, long, ...).   The result is unsigned int and must be
 * cast to any desired pointer type.
 */
#define __DARWIN_ALIGNBYTES     (sizeof(__darwin_size_t) - 1)
#define __DARWIN_ALIGN(p)       ((__darwin_size_t)((__darwin_size_t)(p) + __DARWIN_ALIGNBYTES) &~ __DARWIN_ALIGNBYTES)

#define      __DARWIN_ALIGNBYTES32     (sizeof(__uint32_t) - 1)
#define       __DARWIN_ALIGN32(p)       ((__darwin_size_t)((__darwin_size_t)(p) + __DARWIN_ALIGNBYTES32) &~ __DARWIN_ALIGNBYTES32)

#endif /* defined (__arm__) || defined (__arm64__) */

#endif /* _ARM__PARAM_H_ */