Newsitem for review... This goes back to discussions long ago with Kent.
We weren't sure then if Portage can handle it. However, since it can handle 
Python... :P Binary package support now makes the USE_EXPAND hard-necessary.

The corresponding patch series is following in a few minutes as reply.


Title: dev-lang/perl useflags become a PERL_FEATURES use-expand
Author: Andreas K. Huettel <dilfridge@gentoo.org>
Posted: 2024-05-10
Revision: 1
News-Item-Format: 2.0

Starting with dev-lang/perl-5.38.2-r3, the three use flags "debug", 
"ithreads", and "quadmath" of Perl are renamed into a common
use-expand variable, PERL_FEATURES, which should be set *globally*
in make.conf.

If you do *not* want to change the settings of your Perl, make
sure that the new variable PERL_FEATURES contains the same settings
that were applied to your Perl all along. 

I.e., if you have dev-lang/perl[ithreads] installed, make sure
to now set in make.conf
  PERL_FEATURES="ithreads"

If you *want* to change the settings of your Perl, make sure to
run perl-cleaner after rebuilding dev-lang/perl:
  perl-cleaner --modules ; perl-cleaner --force --libperl

Background: This change in the structure of the useflags is a
first step towards a solution of bug 930123. The three useflags
influence not only how Perl itself is installed, but also all 
Perl modules...


-- 
Andreas K. Hüttel
dilfridge@gentoo.org
Gentoo Linux developer 
(council, comrel, toolchain, base-system, perl, libreoffice)
https://wiki.gentoo.org/wiki/User:Dilfridge