Description:
------------
I notified that code like

echo date('r', strtotime('1 day ago'));

always returns 00:00:00 time for last day, but if I use code

echo date('r', mktime(date('h'), date('i'), date('s'), date('m'), date('d') - 1, date('Y')));

it returns date representation with a correct time, exactly one day ago.
Why it always returns midnight time for last day?
If I use '24 hours ago' or '84600 seconds ago' - I got the same wrong time of midnight.

Reproduce code:
---------------
echo date('r', mktime(date('h'), date('i'), date('s'), date('m'), date('d') - 1, date('Y'))), '<br />';
echo date('r', strtotime('1 day ago')), '<br />';
echo date('r', strtotime('24 hours ago')), '<br />';
echo date('r', strtotime('86400 seconds ago')), '<br />';

Expected result:
----------------
Wed, 1 Sep 2004 12:48:54 +0400
Wed, 1 Sep 2004 12:48:54 +0400
Wed, 1 Sep 2004 12:48:54 +0400
Wed, 1 Sep 2004 12:48:54 +0400


Actual result:
--------------
Wed, 1 Sep 2004 12:48:54 +0400
Wed, 1 Sep 2004 00:00:00 +0400
Wed, 1 Sep 2004 00:00:00 +0400
Wed, 1 Sep 2004 00:00:00 +0400