[gentoo-user] Update circle

["Zoltán Kócsi" <zoltan@bendor.com.au>]

I have a Gentoo machine, which has not been updated for a while. Quite
a long while, actually.

Now I needed to install a package, and I did so. It went up, no
problem. Except that it relies on a newer version of openrc than
what's on the system. From here it's all downhill:

emerge openrc:
- Fails, as the current portage is EAPI 5 (whatever that is), thus all
  EAPI 6 packages are masked. Must upgrade portage.

emerge portage:
- Fails, as it needs tar-1.30 and the installed tar is 1.27. Must update
  tar.

emerge tar:
- Fails, as tar-1.30 needs EAPI 6. Must upgrade portage.

It seems that I'm kind of stuck. Wiping the disk and rebuilding the
system from scratch is absolutely not an option, the existing (and
running) system must be updated somehow.

I would appreciate any advice, I'm in complete darkness about the
internal workings of portage (would be happy to find some detailed docs
about that, by the way, preferably in PDF).

Thanks in advance,

Zoltan