Bug in parsing $DISPLAY

[Paul Fox]

GNUSTEP GUI 0.7.8
        BACK 0.7.8
        BASE 1.3.3

If you have your environment variable like this:

        DISPLAY=89.0.0.22:0

then the startup code fails to parse it correctly and you get weird X
errors about XCreateGC failing. In my environment, DISPLAY is set
by exceed hummingbird and it took me some time to realise this was what
was causing the problem. Setting it to 

        DISPLAY=hostname:0

made it work (well nearly but thats for another bug report :-) )