[Buildroot] [PATCH 3/6] package/Makefile.in: Use gcc spec files for PIE build flags

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

On Sun, 12 Aug 2018 07:49:19 -0500, Matthew Weber wrote:

> > So I don't think we need to wrap "ld", as ld shouldn't be used
> > directly. The only packages that should use "ld" directly are things
> > like the Linux kernel or bootloaders.
> 
> The current hardening approach is trying to cover the cases where
> packages are still using ld directly and have other incompatible flags
> set (static/shared/r).  I don't have the exact list but I believe
> busybox is even one of those and others like valgrind, boost, etc who
> use the "shared" flag and adding "pie" causes a compile failure.  So
> we do still need to cover the ld case or go patch packages.

I find it weird that those packages are using "ld" directly, because if
that's the case, we would have build failures on some mips64
configurations.

> What I could do is move the cc1 spec file conditional add of PIE into
> the wrapper.  Then leave the LDFLAGS as we have them and the
> associated spec file that does a conditional add of "pie".  This would
> prevent us from wrapping the ld tool and keep the existing wrapper
> approach consistent.

If we really need to do some custom logic around ld, then I believe I'd
prefer to have a wrapper for it as well, to keep things consistent. But
of course, Arnout's opinion on the matter would be welcome.

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com