[crossfire] compilation of server broken on certain systems

[Todd Mitchell]

I think this is a simple misunderstanding of intent, no one would expect 
you to install to /

configure --prefix=/<pathto install>

you have to be able to write to <pathtoinstall>

for example configure --prefix=/usr/local/crossfire wher eyour user owns 
/usr/local/crossfire or --configure-prefix=/home/youraccount/crossfire