$ grep 'CLOCKS_PER_SEC' /usr/include/time.h
#define CLOCKS_PER_SEC (__DARWIN_CLK_TCK)
$ grep '#include' /usr/include/time.h
#include <_types.h>
#include <machine/_limits.h> /* Include file containing CLK_TCK. */
#include <sys/cdefs.h>
#include <xlocale/_time.h>
$less /usr/include/machine/_limits.h
/* This is the `system' limits.h, independent of any particular
compiler. GCC provides its own limits.h which can be found in
/usr/lib/gcc, although it is not very informative.
This file is public domain. */
#if defined (__ppc__) || defined (__ppc64__)
#include <ppc/limits.h>
#elif defined (__i386__)
#include <i386/limits.h>
#else
#error architecture not supported
#endif

$ grep '__DARWIN_CLK_TCK' /usr/include/i386/_limits.h
#define __DARWIN_CLK_TCK 100 /* ticks per second */

MacOSXだと100かよ
手間かけさせがって(´･ω･｀)ぶちころすぞ