add missed NULL_DATE

diff --git a/mod/events.php b/mod/events.php
index a2f3ec39a45c0bb33d9b9093f43526c0bd778fb7..60e7b9f39076bf40c7b361afc05ebe9e987b7d5b 100644 (file)
--- a/mod/events.php
+++ b/mod/events.php
@@ -98,7 +98,7 @@ function events_post(App $a) {
                goaway($onerror_url);
        }
 
-       if ((! $summary) || ($start === '0000-00-00 00:00:00')) {
+       if ((! $summary) || ($start === NULL_DATE)) {
                notice(t('Event title and start time are required.') . EOL);
                if (intval($_REQUEST['preview'])) {
                        echo t('Event title and start time are required.');