Created attachment 528250 [details] output of emerge -v quake3 It's obviously a linker issue. There's a build log in the attachment to back this claim up.
On a bright side, this issue is rectified in the latest git commit of ioquake3.
Package was removed from Gentoo ebuild repo in commit 9e2a01c4881b67200d0a43ab7d6f147d6e5ac2aa.