__has_include
#ifndef __has_include
#if !defined HAVE_GETTEXT && defined __has_include
# if __has_include(<libintl.h>)
#if !defined HAVE_SYS_STAT_H && defined __has_include
# if !__has_include(<sys/stat.h>)
#if !defined HAVE_UNISTD_H && defined __has_include
# if !__has_include(<unistd.h>)
#if !defined HAVE_STDINT_H && defined __has_include
#if !defined HAVE_STDCKDINT_H && defined __has_include
# if __has_include(<stdckdint.h>)
# ifdef __has_include
# if __has_include(<sys/random.h>)