gnu-getopt: update file URL

The original file URL has changed.

```
$ curl -v http://software.frodo.looijaard.name/getopt/files/getopt-1.1.5.tar.gz
* Hostname was NOT found in DNS cache
*   Trying 212.238.236.230...
* Connected to software.frodo.looijaard.name (212.238.236.230) port 80 (#0)
> GET /getopt/files/getopt-1.1.5.tar.gz HTTP/1.1
> User-Agent: curl/7.37.1
> Host: software.frodo.looijaard.name
> Accept: */*
>
< HTTP/1.1 302 Found
< Date: Thu, 13 Nov 2014 14:37:13 GMT
* Server Apache/2.2.22 (Debian) is not blacklisted
< Server: Apache/2.2.22 (Debian)
< Location: http://frodo.looijaard.name/project/getopt
< Content-Length: 321
< Content-Type: text/html; charset=iso-8859-1
<
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>302 Found</title>
</head><body>
<h1>Found</h1>
<p>The document has moved <a href="http://frodo.looijaard.name/project/getopt">here</a>.</p>
<hr>
<address>Apache/2.2.22 (Debian) Server at software.frodo.looijaard.name Port 80</address>
</body></html>
* Connection #0 to host software.frodo.looijaard.name left intact
```