Re: [gentoo-dev] Supporting both Qt4 and Qt5 builds

[Johannes Huber]

Am Sonntag, 10. August 2014, 14:51:45 schrieb Georg Rudoy:
> Hi,
>
> I'm thinking of converting a few ebuilds (x11-libs/qwt,
> dev-libs/kqoauth, net-libs/qxmpp among them) to support building with
> both Qt4 and Qt5.
>
> Should this better be done by adding the corresponding useflags (qt4
> and qt5 respectively) or by slotting? The pros and cons for each, off
> the top of my head:
>
> slotting:
> + Allows having different use flags for qt4 and qt5 builds (can't
> think why that would be needed in the above examples though).
> - Possibility of exponential growth of the number of slots in case
> slotting would be required according to some other criteria (again,
> can't think why that would be needed in the above examples).
> - Requires keeping two different copies of the same ebuild with
> basically the same build rules, with all the consequences.
>
> useflags:
> + Seems to be easier and doing the required trick.
> + app-text/poppler already does this.
> - Enabling support for previously disabled Qt version requires
> rebuilding the whole library twice.
>
> What's your opinion on this?
>
> I've attached the useflag-based variant as a draft.

Multibuild is prefered.

-- 
Johannes Huber (johu)
Gentoo Linux Developer / KDE Team
GPG Key ID F3CFD2BD