Fix PHP 7.2 warning: count(): Parameter must be an array or an object that implements Countable

program/steps/mail/sendmail.inc

@@ -889,7 +889,7 @@ function rcmail_email_input_format($mailto, $count=false, $check=true)
         else if (preg_match('/<*'.$email_regexp.'>*$/', $item, $matches)) {
             $address = $matches[0];
             $name    = trim(str_replace($address, '', $item));
-            if ($name[0] == '"' && $name[count($name)-1] == '"') {
+            if ($name[0] == '"' && $name[strlen($name)-1] == '"') {
                 $name = substr($name, 1, -1);
             }
             $name     = stripcslashes($name);