Log Message:
update to 2.6.8
This is a major update, I couldn't find the relevant changecogs but
the last one. A couple of bugfixes.

pkgsrc note: Since base and plugins are seperate distfiles now, we
could abandon the Makefile.common or at least part of its complexity.
I'll leave this to the MAINTAINER.
Also, I'd suggest to rip -plugins into parts - many are too exotic.
(There are also some new which are not built, I've just kept status quo.)