I'm not all too experienced with how ./configure and Makefiles work, and I'd rather not mess my 0.5 install up, so I figured I'd better ask

I'm running Gentoo (2.6.18), 0.5.0 is installed to /usr/games/bin/openttd with data in /usr/share/games/openttd. I'd like the nightly to be installed to /usr/games/bin/openttd-nightly with data in /usr/share/games/openttd-nightly.
Thankful for any help