The syntax of /etc/portage/mirrors should be the same as that of thirdpartymirrors, so why not adjust gentoo.vim from gentoo-syntax like this: <au BufNewFile,BufRead /thirdpartymirrors >au BufNewFile,BufRead {*/thirdpartymirrors,/etc/portage/mirrors}
SVN r77:78, thanks.
Release 20041127, thanks