Fix mirror-info.php to work on PHP8 (arg order to join/implode)

Author: sgolemon

mirror-info.php

@@ -29,7 +29,7 @@ function_exists('hash_file') &&
 // Gets all available sqlite versions for possible future sqlite wrapper
 $sqlite = get_available_sqlites();
 
-$exts = join(get_loaded_extensions(), ',');
+$exts = implode(',', get_loaded_extensions());
 
 echo join('|', array(
     $MYSITE,            	// 0 : CNAME for mirror as accessed (CC, CC1, etc.)