general-concepts/use-flags: give guidance on IUSE defaults

[thesamesam]

Signed-off-by: Sam James sam@gentoo.org

[orlitzky]

Because portage treats flags as off by default, and because of the default USE_ORDER, it's much harder for people to disable flags that are default-on than it is for them to enable flags that are not.

Making this a de-facto policy is really annoying for the people who want to enable only what they want and leave everything else off. (That said, it's already a pain in the ass, because every maintainer does whatever he wants at the moment, and many use IUSE defaults as their own personal make.conf replacement.)

A policy like "IUSE defaults should only be set when the package would otherwise be severely handicapped" would be more in line with our tooling.

[orlitzky]

Also, in my experience, many upstreams use configure.ac as their own personal make.conf replacement. In those cases, standardizing what the main developer likes to use on his machine isn't going to produce very consistent results.

[sbraz]

A policy like "IUSE defaults should only be set when the package would otherwise be severely handicapped" would be more in line with our tooling.

I like the general idea.

[thesamesam]

yes, that alternative is fine with me; the intention here is to give some guidance rather than none as is the status quo