Description:
------------
After a file upload, the $_FILES array does not faithfully reflect the structure of the form from which the upload was made. An input with the valid HTML name of 'a.b' becomes the key 'a_b' in the $_FILES array.

The same is true of the other request superglobals.

The PHP manual says that an array index can be any string, and the HTML 5 rec says that the name attribute can be CDATA. 

Now that register_globals is on its last legs in the community, could you make it so that the dot transformation happens only when you explictly extract() or import_request_variables()

Reproduce code:
---------------
<form enctype="multipart/form-data" method="POST">
    <input name="a.b" type="file" />
    <input type="submit" />
</form>

Expected result:
----------------
Something like this:

$_FILES is array ( 
'a.b' => array ( 
  'name' => '5364-16.jpg', 
  'type' => 'image/jpeg', 
  'tmp_name' => 
  '/tmp/php7vvvc0', 
  'error' => 0, 
  'size' => 66554, ), 
)

Actual result:
--------------
$_FILES is array ( 
'a_b' => array ( 
  'name' => '5364-16.jpg', 
  'type' => 'image/jpeg', 
  'tmp_name' => 
  '/tmp/php7vvvc0', 
  'error' => 0, 
  'size' => 66554, ), 
)