merge r3473, r3474, r3385, r3386, r3537: signal processing stability: *) use sys_errlist[] in signal handler instead of non Async-Signal-Safe strerror_r() *) do not update time in the timer signal handler, since localtime_r() is not Async-Signal-Safe function *) use previously cached GMT offset value to update time from a signal handler *) change ngx_time_update() interface since there are no notification methods those return time *) introduce ngx_time_sigsafe_update() to update the error log time only *) change ngx_time_update() interface

--- a/src/event/modules/ngx_select_module.c
+++ b/src/event/modules/ngx_select_module.c
@@ -266,8 +266,8 @@ ngx_select_process_events(ngx_cycle_t *c
         err = 0;
     }
 
-    if (flags & NGX_UPDATE_TIME) {
-        ngx_time_update(0, 0);
+    if (flags & NGX_UPDATE_TIME || ngx_event_timer_alarm) {
+        ngx_time_update();
     }
 
     ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,