Add timer_cmp() utility function to compare two timevals.

This is preferable to using time_diff() to compare two timevals, because
time_diff() gives its result as a 'double' which only has 53 bits of
precision.

Also switch a couple of places from using time_diff() to using
this function.

include/ircaux.h

@@ -82,6 +82,7 @@ struct timeval BX_get_time 	(struct timeval *);
 double 	BX_time_diff 		(struct timeval, struct timeval);
 double time_since(const struct timeval *tv_from);
 double time_until(const struct timeval *tv_to);
+int time_cmp(const struct timeval *a, const struct timeval *b);
 char *	BX_plural 			(int);
 int	BX_time_to_next_minute 	(void);
 char *	BX_remove_trailing_spaces 	(char *);

source/ircaux.c

@@ -1764,6 +1764,15 @@ double time_until(const struct timeval *tv_to)
 	return BX_time_diff(tv_now, *tv_to);
 }
 
+/* Compare two timevals - returns 1, 0 or -1 if a is >, = or < b */
+int time_cmp(const struct timeval *a, const struct timeval *b)
+{
+	if (a->tv_sec == b->tv_sec)
+		return (a->tv_usec > b->tv_usec) - (a->tv_usec < b->tv_usec);
+	else
+		return (a->tv_sec > b->tv_sec) - (a->tv_sec < b->tv_sec);
+}
+
 int BX_time_to_next_minute (void)
 {
 	time_t now = time(NULL);

source/timer.c

@@ -176,7 +176,7 @@ extern	void ExecuteTimers (void)
 	get_time(&now1);
 	
         parsingtimer = 1;
-	while (PendingTimers && BX_time_diff(now1, PendingTimers->time) < 0)
+	while (PendingTimers && time_cmp(&now1, &PendingTimers->time) >= 0)
 	{
 		int old_refnum = current_window->refnum;
 
@@ -587,7 +587,7 @@ static char *schedule_timer (TimerList *ntimer)
 	/* we've created it, now put it in order */
 	for (slot = &PendingTimers; *slot; slot = &(*slot)->next)
 	{
-		if (BX_time_diff((*slot)->time, ntimer->time) < 0)
+		if (time_cmp(&(*slot)->time, &ntimer->time) > 0)
 			break;
 	}
 	ntimer->next = *slot;