diff --git a/configure.ac b/configure.ac
index 4d2ba37..77a4968 100755
--- a/configure.ac
+++ b/configure.ac
@@ -987,7 +987,31 @@
AC_FUNC_STRTOD
AC_FUNC_VPRINTF
-AC_CHECK_FUNCS([_exit atexit clock clock_gettime directio execvp floor fork ftime ftruncate getcwd getpid getexecname getdtablesize getpagesize getrlimit getrusage gettimeofday gmtime_r localtime_r lstat memmove memset mkstemp munmap _NSGetExecutablePath pclose _pclose poll popen _popen posix_fadvise posix_fallocate posix_madvise posix_memalign pow pread pwrite raise rand_r readlink readdir_r realpath select seekdir setlocale sqrt setvbuf stat strchr strerror_r strrchr strcspn strdup strpbrk strspn strstr strtol symlink sysconf sigemptyset sigaction strerror strlcat strlcpy strcasecmp strncasecmp telldir tempnam times usleep vsprintf vsnprintf waitpid _wfopen _wstat])
+AC_CHECK_FUNCS([_exit atexit clock directio execvp floor fork ftime ftruncate getcwd getpid getexecname getdtablesize getpagesize getrlimit getrusage gettimeofday gmtime_r localtime_r lstat memmove memset mkstemp munmap _NSGetExecutablePath pclose _pclose poll popen _popen posix_fadvise posix_fallocate posix_madvise posix_memalign pow pread pwrite raise rand_r readlink readdir_r realpath select seekdir setlocale sqrt setvbuf stat strchr strerror_r strrchr strcspn strdup strpbrk strspn strstr strtol symlink sysconf sigemptyset sigaction strerror strlcat strlcpy strcasecmp strncasecmp telldir tempnam times usleep vsprintf vsnprintf waitpid _wfopen _wstat])
+
+#
+# Check for clock_gettime().
+#
+AC_SEARCH_LIBS(clock_gettime, rt,
+[
+ AC_DEFINE([HAVE_CLOCK_GETTIME],[1],[Define to 1 if you have clock_gettime.])
+ AC_MSG_CHECKING([whether clock_gettime supports CLOCK_REALTIME])
+ AC_COMPILE_IFELSE(
+ AC_LANG_PROGRAM(
+ [[#include <time.h>]],
+ [[clockid_t clockType = CLOCK_REALTIME;]]),
+ [
+ AC_MSG_RESULT(yes)
+ AC_DEFINE([HAVE_CLOCK_REALTIME],[1],
+ [Define to 1 if clock_gettime supports CLOCK_REALTIME.])
+ ],
+ AC_MSG_RESULT(no)
+ )
+ ],
+ [
+ AC_CHECK_FUNCS([gettimeofday ftime], [break])
+ ]
+)
########
#