After replacing fam with gamin and an emerge --newuse, I noticed that the fam USE flag had been turned off. This is attributable (it seems) to the fact that /usr/portage/profiles/base/use.defaults has the line fam app-admin/fam but no mention of gamin. I would propose that the above line be replace with fam virtual/fam Reproducible: Always Steps to Reproduce:
*** This bug has been marked as a duplicate of 67170 ***