if setting PHP ini error_reporting value from within Apache one has to use the effective numerical value or Drupal will not log anything at all

drupal/drupal-apache.conf

@@ -82,7 +82,7 @@ php_admin_flag    register_globals              off
 php_admin_flag    session.auto_start            off
 php_admin_value   session.save_handler          user
 php_admin_value   session.cache_limiter         none
-php_admin_value   error_reporting               E_ALL&~E_NOTICE
+php_admin_value   error_reporting               6135
 php_admin_value   memory_limit                  64M
 php_admin_value   mbstring.http_input           pass
 php_admin_value   mbstring.http_output          pass