Prevent server from stalling if time goes backwards (M. Vallevand)

ChangeLog

@@ -62,6 +62,7 @@ v.0.5dev (ongoing development)
  + new driver irtrans (Phant0m / Aron Parsons)
  + serialVFD driver: support Siemens/Wincor Nixdorf BA63/66 (Stefan Herdler)
  + new client lcdident.pl (Ethan Dicks)
+ * server: prevent stalling if time goes backwards (M. Vallevand)
 
 v.0.5.2
  * fix switching on/off the Load screen in lcdproc client using the menu

server/main.c

@@ -810,7 +810,7 @@ do_mainloop(void)
 #ifndef WIN32
 		gettimeofday(&t, NULL);
 		t_diff = t.tv_sec - last_t.tv_sec;
-		if ((t_diff + 1) > (LONG_MAX / 1e6)) {
+		if ( ((t_diff + 1) > (LONG_MAX / 1e6)) || (t_diff < 0) ) {
 			/* We're going to overflow the calculation - probably been to sleep, fudge the values */
 			t_diff = 0;
 			process_lag = 1;