During my upgrade from 1.3 to 1.4 I got an error while running the command:
# emerge -auDN @world --jobs=3 --exclude dev-lang/perl
So i got the error "Package 'dev-db/mysql-connector-c-8.0.16' NOT merged due to file collisions."
The detected file is /usr/lib64/pkgconfig/mysqlclient.pc
I checked with "portageq" who's the owner and looks like it's dev-db/mysql-5.7.23
Not sure if it's an human mistake (me) or if it's a portage bug...