[Buildroot] [PATCH] Makefile: work around a bug in newly released make 4.3

[Yann E. MORIN <yann.morin.1998@free.fr>]

Thomas, All,

On 2020-03-04 14:04 +0100, Thomas Petazzoni spake thusly:
> On Wed,  4 Mar 2020 13:53:30 +0100
> "Yann E. MORIN" <yann.morin.1998@free.fr> wrote:
> 
> > Several users of rolling-release distributions have been reporting on
> > IRC that Buildroot is broken now that they have switched to the newly
> > released make 4.3.
> > 
> > It turns out that the constructs we use to generated and ionclude the
> > internal br2-external related fragments is no longer working with
> > make-4.3.
> > 
> > Indeed, an upstream bug report [0] seems to imply that it so far was
> > working by chance. There has been no further feedback, whether this is
> > really considered a fix or a regression...
> What does [0] points to ?

Well, to the upstream bug report, obviously! ;-]
Fixed, thanks.

> > In the meantime, we add a workaround that fixes the issue, and should
> > not break on older make versions either (verified on all relevant
> > versions: 3.81, 3.82, 4.0, 4.1, and 4.2).
> Could you give more details about how the workaround fixes the issue ?

Oh yes, I surely can: it was suggested in that bug report! ;-)

Honestly, I am not sure I totally understood the reason, or the
workaround...

> > Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
> > ---
> >  Makefile | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/Makefile b/Makefile
> > index 31624f77a2..c22c1d8980 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -188,6 +188,9 @@ ifneq ($(BR2_EXTERNAL_ERROR),)
> >  $(error $(BR2_EXTERNAL_ERROR))
> >  endif
> >  
> > +# Workaround bug #57676 in make-4.3
> Perhaps an http:// link instead of just #57676 ?

Even if it is in the commit log now?

Regards,
Yann E. MORIN.

> > +$(BASE_DIR)/.br2-external.mk:;
> > +
> >  # To make sure that the environment variable overrides the .config option,
> >  # set this before including .config.
> >  ifneq ($(BR2_DL_DIR),)
> 
> Thanks!
> 
> Thomas
> -- 
> Thomas Petazzoni, CTO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com

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