Fresh drupal install shows drupal core warning
Since you used git clone, you probably pulled from the HEAD and are running a development version of Drupal. Your Drupal installation does not have an official version number, so it cannot be detected. You can install Drupal with composer, download the zip, or try to clone a tagged release (I always used composer so I am not sure if a tagged release works).

As for the 32/64 bit warning. Depending on the PHP version you have installed, you can run a 32bit PHP installation on a 64bit OS. I suppose that is the root of your problem.