[gentoo-user] Howto unmask use flag

["Jörg Schaible" <joerg.schaible@gmx.de>]

Hi,

how can I unmask a use flag masked in profiles/base/package.use.mask? If I set the flag for the package in /
etc/portage/package.use it is simply ignored.

Concrete example: My /etc/portage/package.use contains the line:

  dev-java/oracle-jdk-bin:9 doc gentoo-vm source

However the flag 'gentoo-vm' is always ignored because it is masked in profiles/base/package.use.mask with 
the line:

  dev-java/oracle-jdk-bin:9 gentoo-vm

What's the proper procedure to unmask the flag locally?

(Yes, I know it is experimental and yes I know what I am doing with it. I already use eselect for older EA builds 
of Java 9 with 1.9 slot and new EA builds of Java 10 - just not the "official" Java 9 from the tree.)

Cheers,
Jörg