Bug#1133272: dpkg-buildflags: please include LFS_CFLAGS and LFS_LDFLAGS

Hi!

On Sat, 2026-04-11 at 13:46:06 +0300, Martin-Éric Racine wrote:
> Package: dpkg-dev
> Version: 1.23.7
> Severity: important
> X-Debbugs-Cc: [email protected]

> In my packages, I currently have to manually include the following in
> debian/rules:

> export DEB_CFLAGS_MAINT_APPEND  +=$(shell getconf LFS_CFLAGS) $(HARDENING_CFLAGS)
> export DEB_LDFLAGS_MAINT_APPEND +=$(shell getconf LFS_LDFLAGS) $(HARDENING_LDFLAGS)
> 
> It would be nice if dpkg-buildflags provided these for us.

The getconf interface is problematic as it does not correctly support
cross-building. I clarified this in the lintian tag for the LFS
support with:

  https://salsa.debian.org/lintian/lintian/-/commit/ba9c7fd96801e3c796d0233b4f7432e55dffe057

but now that the lintian LFS tag has been removed, that got lost.

In any case, dpkg-buildflags already supports setting LFS flags with:

  export DEB_BUILD_MAINT_OPTIONS = abi=+lfs

which should support cross-building correctly.

I was going to close this report as invalid, but I guess I can instead
document that the getconf interface should not be used in the
dpkg-buildflags man page (although I'm not sure it would have helped
here, as I assume the man page was not checked?).

Thanks,
Guillem