I'm currently doing a 540-packages system update. I'm at about package 390: avifile It stops with "FATAL: both /usr/share/aclocal/wine.m4 and /usr/local/share/aclocal/wine.m4 exist; you must manually delete one of them". I've seen this error message with another package alraedy. I just manually removed the file and went on. Now that it happened twice, I thought I might file a bugreport. Reproducible: Always Steps to Reproduce: emerge avifile
Gentoo does not - or at least should not ;) - install anything into /usr/local; so you can safely delete /usr/local/share/aclocal/wine.m4. If you still think that the offending file was installed by Gentoo, then run 'equery b /usr/local/share/aclocal/wine.m4' to find out to ebuild this file belongs to, but I suppose that you won't find anything. If you do, then feel free to reopen this bug.