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Date: Sat, 5 Feb 2011 16:31:43 +0100
From: Enrico Weigelt <weigelt@metux.de>
To: gentoo-embedded@lists.gentoo.org
Subject: Re: [gentoo-embedded] CBUILD= HOSTCC=-gcc
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* Christoph Spielmann <spielc@gmail.com> schrieb:

> Okey but all these things are in the end x86-processors. Some support 
> flags that other's won't but in the end they are basically all the same 
> arch. So my suggestion would've been: use a chroot-environment for such 
> a case.

Well, these subarchs can be *very* different, especially when it
comes to things like fp or vector ops, etc. You definitively don't
want some package to be so "clever" to automatically build in
cpu-optimized or even cpu-specific code just because the configure
script sees it runs on that cpu (in recent years, I had many of
those cases). And you also don't want it to switch certain features
by existance/absence of certain devices, procfs or sysfs files.
(similarily you dont wan't implicit features switches introducing
certain dependencies just by the existence of certain libs).

In the end, the clean solution is always to crosscompile with an
(per-package) minimal sysroot.

> In my eyes it only makes sense to use cross-compilation (including all 
> the hassles that you will come across by using it) if you need (or want) 
> to build stuff for another architecture or machine, that is not 
> powerfull enough for compilation tasks itself. E.g. arm5-code on a 
> x86_64-environment

If you only look on the scope of one specific distro (and expect the
target system to be relatively up2date), yes. In generic case, no.


cu
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