Dnia 2014-06-11, o godz. 13:12:38
Chí-Thanh Christopher Nguyễn <chithanh@gentoo.org> napisał(a):

> > REQUIRED_USE="
> >     curl_ssl_winssl? ( elibc_Winnt )
> >     ssl? (
> >         ^^ (
> > [...]
> >         )
> >     )"  
> 
> I don't like this. If the user specifies several SSL providers in
> make.conf, it should mean that any of these is fine and the ebuild can
> choose an arbitrary one. The exactly-one-of operator would cause emerge
> to complain in this case and possibly force the user to have complex
> package.use setups.

Your idea comes with three significant drawbacks:

1. USE flag setups become unclear -- user sees five different SSL
providers turned on and has no clue which one is actually used.

2. You create 2^n-1 valid USE flag combinations which map to n
different file sets. This means that there are 2^n-n-1 useless USE flag
combination which make matching binary packages a PITA.

3. There is no clean way of enforcing SSL provider match between
packages. Wasn't this thread initially about curl and rtmpdump
requiring matching flags?

-- 
Best regards,
Michał Górny