Re: multiarch compatible cross compilers for Jessie

[Jean-Christian de Rivaz <jc@eclis.ch>]

Le 05. 10. 14 20:01, Paul Boddie a écrit :
> OK, as you know, I managed to build a toolchain recently, specifically for an
> i386 build platform and a mipsel target platform. Aside from the occasional
> dependency disruption where I managed to update various gcc-related i386
> packages and then had to wait for the mipsel dependencies to catch up (or be
> told that the gcc-4.9 build dependencies needed all my essential packages to
> be removed in order for them to be installed themselves), and apart from the
> dh_strip problem mentioned a few days ago (where I'd managed to ignore the
> workaround suggested by YunQiang Su), it all seemed to work.
>
> One thing that wasn't clear and doesn't seem to be resolved, however, and
> which seems to obstruct package cross-building is the matter of the generic
> gcc program or symbolic link:
>
> https://bugs.launchpad.net/ubuntu/+source/gcc-defaults-armel-cross/+bug/600930
>
> I suppose that the "resolution" of this matter by providing the gcc-defaults-
> armel-cross package isn't really a proper solution. Unless one manually makes
> a symbolic link for gcc (in my case, mipsel-linux-gnu-gcc, I guess), it
> appears necessary for me to edit debian/rules files to set CC manually
> wherever configure is called, although I could be missing some debhelper
> mechanism that would normally be invoked to deal with this.
>
> Another thing is the matter of programs like pkg-config:
>
> https://bugs.launchpad.net/ubuntu/+source/gcc-defaults-armel-cross/+bug/771569
>
> Again, the suggested solution of manually making a symbolic link for a target
> platform seems like a bit of a hack, really, but it does seem to make cross-
> builds work without any extra effort. I suppose no further consensus was
> reached about providing platform-specific pkg-config programs or links.
>
> Anyway, after a couple of successful cross-builds (involving the libvorbisidec
> and sdl-mixer1.2 source packages), those are my experiences so far. Thanks to
> everyone who has made this possible!

Many thanks Paul for sharing your experience and tips regarding 
multiarch compatible cross
compilers for Jessie. It show that the emDebian effort are going forward.

Having not the required time to investigate the same route, I finally 
tried a radically
different approach: I now compile and build the specific packages of my 
applications
directly on the armhf target (536MHz Cortex-A5), using his native build 
infrastructure.
This immediately terminate all cross building problems down with 
surprisingly little
downside. The compilation is slow, but not to the point of making the 
whole process
ineffective. I can only use terminal tools (instead of graphical IDE 
tools), but as I usually
work on remote machines, this change nothing for me. As usual, I use git 
to push the
source code from the target to the internal server and reprepro + rsync 
to upload the
package from the target to my client's servers. Cross-compiler is still 
required to build
initial bootloader and all kernel as his big size make the process far 
too slow on the
target. The two are easy to handle because there basically have no 
dependency. The
most frustrating is the long time need by almost any apt-* operations to 
read the
packages informations.

I am confident that more powerful armhf machines where Debian jessie is 
easy to run
exists and even more will be in the future, so this route might become 
my default route
for some time. I will still keep an eye to the multiarch cross-building 
progress.

Jean-Christian