This include is useless and can be removed.
This syscall has been strongly deprecated for ages and the plugin doesn't use it any more. On old architectures, this include is benign as long as it's unused, on new ones (such as x32) it results in a build failure.
Fix bug #11477
The code included net/if_ppp.h headers, but the code doesn't
use any function from this header. FreeBSD doesn't ship if_ppp.h
anymore and it broke compilation.
Clarify that wormulon is under GPL2 or later, and, after agreeing witn
Bernhard Walle, relicense xfce4-netload-plugin under GPL2 or later,
instead of GPL2 strictly.