With the caveat; 'this is my first Mac and this has worked exactly once', here we go.
I got an iBook yesterday and, naturally, the first thing I did was begin to install GNU/Linux (specifically, Gentoo) on it. Building from stage 1 or stage 2 caused some problems in that glibc-2.3.3_pre* required gcc-3.3, which are all masked for ppc. Seems like a bootstrap.sh problem (shouldn't it consider such things?), but that's another topic. I was able to build from stage 2 by adding >=sys-libs/glibc-2.3.3 to /etc/portage/package.mask. This would probably have worked from stage 1, but I was frustrated at that point and didn't try.
Now, on to xorg-x11. Brazenly resigned to be a guinea pig, I stopped 'emerge system' while xfree was trying to emerge, in spite of my -X USE flag. Then, I added ~ppc to the KEYWORDS in the xorg ebuild and ran 'emerge xorg-x11', which built successfully. I changed my USE flags back to 'X' and restarted 'emerge system'.
This seems to have satisfied all the virtual-x11 dependencies, as xfree is no longer being called for. Whether I can configure and run it remains to be seen.
Reproducible: Didn't try
Steps to Reproduce:
Marked ~ppc, thanks
I can confirm this (When not using gcc-3.3.3: http://bugs.gentoo.org/show_bug.cgi?id=47249) and I have it configured and working properly. About a million times faster than xfree experimental series.