[W] some installation warnings

[githubertus]

Ubuntu 21.04
PHP 8.0.1 fpm
Ossn 6.1 from Github (6. Oct)

PHP Warning: preg_match(): Compilation failed: invalid range in character class at offset 4 in /var/www/ossn/installation/classes/OssnInstall.php on line 209', referer: installation/?page=settings
PHP Warning: ini_set(): Session ini settings cannot be changed when a session is active in /var/www/ossn/system/start.php on line 35
PHP message: PHP Notice: session_start(): Ignoring session_start() because a session is already active in /var/www/ossn/system/start.php on line 37', referer: installation/?page=settings
PHP Warning: ini_set(): Session ini settings cannot be changed when a session is active in /var/www/ossn/system/start.php on line 35
PHP message: PHP Notice: session_start(): Ignoring session_start() because a session is already active in /var/www/ossn/system/start.php on line 37', referer: installation/?page=account
PHP Warning: ini_set(): Session ini settings cannot be changed when a session is active in /var/www/ossn/system/start.php on line 35
PHP message: PHP Notice: session_start(): Ignoring session_start() because a session is already active in /var/www/ossn/system/start.php on line 37', referer: installation/?page=installed

[lianglee]

I think we need to do

if(session_status() === PHP_SESSION_NONE) in installation session