[oe] RFC: handling of machine/distro features stuff

[Justin Patrin]

On 10/29/06, Marcin Juszkiewicz <openembedded at hrw.one.pl> wrote:
>
> Currently OpenEmbedded use overrides based on DISTRO, MACHINE, TARGET_ARCH
> and few others. I want to suggest start of using also
> {MACHINE,DISTRO}_FEATURES because we have some stuff in metadata which
> make sense only on some targets only - for example madwifi is limited to
> PCI devices only.
>
> Why do this at all? Let me take wpa-supplicant 0.5.x as example.
>
> I'm building own distribution for my PDA devices and want to use latest
> possible software. But wpa-supplicant 0.5.1 depends on madwifi which
> cannot be build because my target device does not have PCI bus support. If
> I remove madwifi stuff from wpa-supplicant recipe then I will get working
> version. But this cannot be pushed back into repo because NSLU2 related
> distros want version with madwifi support.
>
> Solution can be adding checking for pci support in
> {MACHINE,DISTRO}_FEATURES and only then enable madwifi support:
>
> DEPENDS = "gnutls \
> ${@base_contains("DISTRO_FEATURES", "pci", "madwifi", "",d)}"
>
> Same stuff can go into madwifi recipe so it will get skipped if target
> device lack PCI support.
>

It *sounds* like what you want here is basically a USE-flag type of
system. Introducing it as FEATURES flags makes sense to me given that
OE is made for building embedded distros and not for local building,
as portage.

-- 
Justin Patrin