For those experiencing problems with "invalid magic file, disabled" in phpinfo() although everything seems to be set up correctly:
It seems that the real error behind this is that the PHP mime_magic
extension does NOT obey "php_admin_value mime_magic.magicfile" or
"php_value mime_magic.magicfile" directives in httpd.conf, although the
documentation states that mime_magic.magicfile should be settable from
PHP_INI_SYSTEM, i.e., from php.ini and httpd.conf.
Adding the following to php.ini correctly configures mime_magic (using
an Apache 2-supplied magic file):
mime_magic.magicfile = "/etc/apache/magic"
Furthermore, phpinfo() will SHOW any httpd.conf setting of
mime_magic.magicfile that you make, but still not actually USE anything
but what you specified in php.ini!
Hopefully this can help someone. As the mime_magic extension is deprecated, it is not supported anymore, so I guess we can't expect any fixes to this. Even though many scripts still use the mime_magic functionality.