email sender, non standard subdomain

[taur]

site generates sender addresses in the form of wordpress@…
in pluggable.php line 349 to 353 instead of using substr to cut off 'www.' from $sitename use parse_url($sitename)host to make it work with non-standard subdomains aswell

[taur]

need to be:

if(count(explode('.', $sitename)) > 1) {
    $sitename = explode('.', $sitename);
    $sitename = $sitename[count($sitename)-2] . '.' . $sitename[count($sitename)-1];
}

in fact, but won't work for two-segment TLD's such as .co.uk where something more elaborate is needed, see: ​https://gist.github.com/pocesar/5366899

[SergeyBiryukov]

Duplicate of #16805 and #25239.