How can I let users change their password through IMP.

[Jarungwit BOONPERM]

Dear members,
   I follow at "http://www.horde.org/faq/admin/config/index.php#c17"
that config below.
    $default->change_password = 'poppassd.php3';
    $default->poppassd_server = 'MyHostName';
    $default->poppassd_port = '106';

   I download "poppassd.c" from
"ftp://ftp.netwinsite.com/pub/netwinsite/poppassd/poppassd.c".

    But when I compile (gcc poppassd.c -o poppassd), it has error
messages below.

         poppassd.c:146: getopt.h: No such file or directory

     MyHostName is Solaris-2.5.1 with gcc-2.8.1.
Please let me know how to solve this problem ?
		thank you very much.
		     regards,
		    Jarungwit.