SetPermissions.pl --otrs-user=otrs --web-user=apache --otrs-group=apache --web-group=apache "${S}" dies with "Could not set permissions"
Caused by running emerge as user portage. This user has sometimes insufficient file rights. This is the default behaviour since 2013SEP, when the portage FEATURE userpriv was enabled per default. See man make.conf.
Disable this FEATURE using the awesome /etc/portage/package.env file.
Edit this file, adding the following line:
> www-apps/otrs otrs.conf
Then create a folder /etc/portage/env and a file /etc/portage/env/otrs.conf containing the follwing:
> FEATURES="-userpriv"