runtime: If no sem_timedwait, use pthread_cond_timedwait.

From-SVN: r181821
diff --git a/libgo/configure.ac b/libgo/configure.ac
index e19b5f3..576d1a6 100644
--- a/libgo/configure.ac
+++ b/libgo/configure.ac
@@ -456,6 +456,14 @@
 AM_CONDITIONAL(HAVE_STRERROR_R, test "$ac_cv_func_strerror_r" = yes)
 AM_CONDITIONAL(HAVE_WAIT4, test "$ac_cv_func_wait4" = yes)
 
+CFLAGS_hold="$CFLAGS"
+CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+LIBS_hold="$LIBS"
+LIBS="$LIBS $PTHREAD_LIBS"
+AC_CHECK_FUNCS(sem_timedwait)
+CFLAGS="$CFLAGS_hold"
+LIBS="$LIBS_hold"
+
 AC_CACHE_CHECK([for __sync_bool_compare_and_swap_4],
 [libgo_cv_func___sync_bool_compare_and_swap_4],
 [AC_LINK_IFELSE([