Bugzilla Bug 156191

The file /etc/portage/profile/use.mask can be used to modify the profile
use.mask, in particular to unmask locally some flags originally masked for the
profile.

However, these locally unmasked flags do not show up in ufed and thus cannot be
set. (This is particularly annoying since there is no clean way to set these
flags at least "manually" without editing /etc/make.conf *every time* after
calling ufed, although currently the source command might be misused to this
purpose).

I guess the correct solution would be that ufed "appends" /etc/portage/profile
to the list of directories to be read for the cascaded profile.

I happen to have that in the patch for bug #154628, I'm just waiting for it to
be tested, since that specific bug is amd64-specific and I have no amd64
machine.

I had misread your comment 4 to #14628 and had (falsely) thought that this
patch is already contained in 0.40-r4.

I have amd64 and tested the patch now:
The flags mmx sse sse2 (e.g.) showed up and were saved as any other flags.
Locally unmasking also worked as it should (i.e. the unmasked flags were
treated as any other "normal" flag).
Local masking had the expected effect on "normal" flags like e.g. readline
(i.e. readline did not show up anymore and was unselected).
However, local masking had no effect on the "special" flags mmx sse sse2. This
is not a real problem, of course...

(In reply to comment #2)
> However, local masking had no effect on the "special" flags mmx sse sse2. 

Thanks for testing. As it turns out, that's because use.mask overrides
package.use.mask in parent profiles, but I was only letting it override parent
profiles' use.mask. A fixed patch is now in the tree (for ufed-0.40-r5), which
also addresses your bug.