[screen-devel] Patch for displaying inet address in hardstatus

[Berry Octave]

Hi everybody,

after having been using screen a lot on different servers, I though that 
beeing able to display any source address reported by ifconfig could be a 
nice feature.

I've made that patch, which is supposed to work for linux os (it uses ioctl to 
get the addresses from actives interfaces).

Basicly, it adds a file to the build, which offers a AddInetInfo function, 
called in screen.c using the I attribute for hardstatus line.
It prints on it something like "lo:127.0.0.1 eth0:10.0.2.2 wlan0:192.168.5.22" 
(supposing that eth0 and wlan0 are active).

Thanks for comments, review and if possible a merge.

Berry Octave