perl-5.16 does not have a build flag in IUSE. Please update your dependency. If your package is EAPI < 4: > || ( >=dev-lang/perl-5.16 <dev-lang/perl-5.16[-build] ) If your package is EAPI >= 4: > dev-lang/perl[-build(-)] (and maybe take this as an opportunity to update to EAPI 5. :)
Committed to 2.4.35 without a revbump.