update function: only call pcntl_alarm() if it is defined

functions.php

@@ -5365,10 +5365,10 @@
 
 			// We setup a alarm to alert if the feed take more than 300s to update.
 			// => HANG alarm.
-			if(!$from_http) pcntl_alarm(300);
+			if(!$from_http && function_exists('pcntl_alarm')) pcntl_alarm(300);
 			update_rss_feed($link, $line["feed_url"], $line["id"], true);
 			// Cancel the alarm (the update went well)
-			if(!$from_http) pcntl_alarm(0);
+			if(!$from_http && function_exists('pcntl_alarm')) pcntl_alarm(0);
 
 			sleep(1); // prevent flood (FIXME make this an option?)
 		}