RepoConfigLoader: PORTDIR/repos.conf interaction
Remove stray print from last commit.
Delay validation of repos.conf locations/names.

For backward compatibility with locations set via PORTDIR and
PORTDIR_OVERLAY, delay validation of the location and repo.name
until after PORTDIR and PORTDIR_OVERLAY have been processed.
action_sync: use emerge_config parameter
PORTAGE_RSYNC_OPTS: --omit-dir-times

Directory modification times are irrelevant, and preserving them can be
annoying when using squashfs + unionfs, since it can trigger creation
many empty directories in the RW branch.
action_sync: backward compatible parameters
portage.package.ebuild.getmaskingreason.getmaskingreason(): Stop using PORTDIR and PORTDIR_OVERLAY.
emerge --sync: support repo arguments
getmaskingreason: handle UNKNOWN_REPO
egencache: Require --repo option.
Use consistent e-mail address in manuals.
Add warning for missing masters attribute in layout.conf.
egencache: Print warnings for deprecated options.
Add anoncvs gentoo-x86 example in documentation of repos.conf.
Bug #477452: Support force attribute in repos.conf.
emirrordist: Require --repo option, deprecate --portdir and --portdir-overlay
options, support --repositories-configuration option.