$summary this can be useful to me in tinderbox work Just FTR, if the option should do its job before emerge starts, then fine. If the option should do its job before do anything with each ebuild (so done multiple times when e.g. emerge is emerging 10 packages) it should not be compatible with -j
We have FEATURES=fail-clean which is intended for a similar type of scenario. I guess you don't want to use FEATURES=fail-clean because you need to collect some information from PORTAGE_TMPDIR after a build failure? If so, maybe you could automate that by using register_die_hook in /etc/portage/bashrc to register a function to do whatever it is that you need to do.
