Comment 1 for bug 180551

[somewhat edited for brevity...]
const char *get_hostname(void)
{
    /*
     * The gethostname() call is not (or not yet) in ANSI or POSIX, but it is
     * part of the socket interface library. We avoid the more politically-
     * correct uname() routine because that has no portable way of dealing
     * with long (FQDN) hostnames.
     */
    if (my_host_name == 0) {
        if (gethostname(namebuf, sizeof(namebuf)) < 0)
            msg_fatal("gethostname: %m");

postfix doesn't call uname. Sounds like glibc is doing something "helpful".

lamont