Bug#578597: Recommend usage of dpkg-buildflags to initialize CFLAGS and al.

[Raphael Hertzog <hertzog@debian.org>]

Hi,

On Sat, 01 May 2010, Loïc Minier wrote:
> On Wed, Apr 21, 2010, Raphael Hertzog wrote:
> > The desired outcome is that all package grab the values directly from
> > dpkg-buildflags and that we can stop exporting the variables from
> > dpkg-buildpackage. That way calling debian/rules directly and via
> > dpkg-buildpackage should give the same result.
> 
>  I wonder why would we ever want to remove the exports?  To prevent
>  accidental pickup of *FLAGS from the env?

Because they will be useless and induce different behaviour between a raw
debian/rules call and dpkg-buildpackage.

> > CFLAGS=$(shell dpkg-buildflags --get CFLAGS)
> 
>  Would it make sense to recommend:
>     CFLAGS ?= $(shell dpkg-buildflags --get CFLAGS)
>  instead?

IMO no, because we don't want to pickup a value from the environment. If
the user want to alter the flags used by the current build, he should use
the interface offered by dpkg-buildflags (i.e. DEB_CFLAGS_SET/APPEND).

>  Or perhaps:
>     DEB_CFLAGS_SET ?= $(shell dpkg-buildflags --get CFLAGS)
>     [...]
>     ./configure CFLAGS="$(DEB_CFLAGS_SET)"
> 
>  I see that's not in the man page, not sure it would make sense in
>  policy either.

This definitely not, DEB_CFLAGS_SET is for the user not for the maintainer.

Cheers,
-- 
Raphaël Hertzog

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