Re: [gentoo-dev] Getting proper USE_EXPAND variable(s) for multilib

[Alexis Ballier <aballier@gentoo.org>]

On Sun, 20 Jan 2013 20:11:31 +0100
Michał Górny <mgorny@gentoo.org> wrote:

> Hello,
> 
> There is a fair interest in multilib and while still early, it would
> be a good moment to decide on how USE flags to use for it.
> 
> The current attempts are mostly using USE=multilib which is not really
> expressive and poor. What I would go for is a clear variable
> specifying which targets package is built for.
> 
> 
> This raises the following questions:
> 
> 1) do we want the default ABI to be switchable?

I'd say no but I do not see any real problem with it.

> 2) do we want irrelevant ABIs to be visible to emerge users?
> 
> By 2) I mean: do we want the users to see stuff like:
> 
>   MULTILIB_ABIS="amd64_abi1 amd64_abi2 -amd64_abi3 (-ppc64_abi1)
>     (-ppc64_abi2) (-ppc64_abi3) ..."
> 
> or just the relevant part.


just the relevant part, you'd probably need PM support here but showing
it all doesn't hurt, it's just less convenient.

> 
> To be honest, I don't know if there's other way to hide USE flags than
> using USE_EXPAND_HIDDEN. If we want to use that, we'd have to split
> the flags per-arch, i.e. have:
> 
>   MULTILIB_AMD64="abi1 abi2 abi3"
>   MULTILIB_PPC64="abi1 abi2 abi3"
> 
> with appropriate USE_EXPAND_HIDDEN set by profiles.

I don't like that at all.
I'd go for ABI= the union of all the MULTILIB_ABIS variables (if there
is no name collision)
we certainly want skype to depend on libitneeds[abi_x86], not 'amd64?
( libitneeds[abi_amd64_x86] ) x86? ( libitneeds )'


Alexis.