Currently, the gtkmm-2.4.1 ebuild has no requirement of glibmm But without glibmm installed, gtkmm cannot be installed... So the ebuild should include a glibmm requirement ;) Reproducible: Always Steps to Reproduce:
Created attachment 31058 [details, diff] Patches the gtkmm ebuild Adds the glibmm requirement to the gtkmm ebuild...
ok, fix is now already in portage... Thanks to the fast developer :-)