strftime and setlocale compatibility
<p>The manual says php 4,5 for strftime and setlocale.</p>

<p>Does a user need any special extensions to use these? For example I have seen php 5.2 json_encode not work because it was an extension.</p>

<p>I am developing an application that needs to work on many php 5 installations. I want to make sure these functions will work.</p>
