[configure] Detect support for monotonic clock

Quagga has code to support monotonic clock to avoid issues where
time of day changes. The support was incomplete since it was not being
detected by autoconf.

diff --git a/configure.ac b/configure.ac
index 7cf30a80c62b9ef6623f862d7135d5b823188799..c1f618248b5c0e15a19c83c7cac34db580512073 100755 (executable)
--- a/configure.ac
+++ b/configure.ac
@@ -1321,6 +1321,16 @@ AC_TRY_COMPILE([#include <sys/resource.h>
  AC_DEFINE(HAVE_RUSAGE,,rusage)],
  AC_MSG_RESULT(no))
 
+dnl --------------------------------------
+dnl checking for clock_time monotonic struct and call
+dnl --------------------------------------
+AC_CHECK_LIB(rt, clock_gettime,
+[AC_DEFINE(HAVE_MONOTONIC_CLOCK,, Have monotonic clock)
+ LIBS="$LIBS -lrt"]
+)
+
+
+
 dnl -------------------
 dnl capabilities checks
 dnl -------------------