[OE-core] RFC: Separate build dir for autotools

[Otavio Salvador]

Hello Richard,

On Mon, Feb 24, 2014 at 11:58 AM, Richard Purdie
<richard.purdie at linuxfoundation.org> wrote:
> For a while poky and others have been using the seperatebuilddir.inc
> file. This makes ${S} != ${B} and means that ${B} can be wiped when
> configuration changes.
>
> This helps deal with the fact that autotools and friends are not
> particular good at rebuilding things that change. The recent libcheck
> upgrade which broke bluez4 builds is but one example of the kind of
> problem we can hit. Sadly bluez4 doesn't work for S!=B so it didn't
> protect against that issue but it does protect other packages.
>
> I'd really love to switch the default in autotools.bbclass to make this
> the default and then have broken packages opt out of it.
>
> I can deal with OE-Core and make sure the metadata there is updated, my
> bigger worry is what this would do to other layers.
>
> The options I can see are therefore basically:
>
> a) We change the default in autotools.bbclass and fix things that break

+1

I think it is better to fix this sooner than later. This indeed helps
improve the build stability so I think this is better to default to
the better options; adding an extra class for it is the wrong way in
my point of view and we'll "support" the wrong use of it. I think the
exceptions are better covered if we keep it explicit in a var and easy
to spot in a git grep.

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
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