Status of cross-compilation in Wheezy?
Greetings all,
Would someone please confirm or correct my understanding of the state
of cross-compilation in Wheezy? Here's what I've synthesized from
wikis, blogs, e-mail archives, and firsthand experience:
With Wheezy comes the beginnings of multiarch, an exciting new world
in which, e.g., the armel package of libexpat1 can be installed on an
amd64 workstation via
apt-get install libexpat1:armel
or in some cases
apt-get build-dep -a armel $other
Theoretically, that armel library can be used by a cross-compiler;
*however*, that glorious future is not yet here. The cross-compilers
in the http://emdebian.org/debian Wheezy repository do not yet look
for foreign libraries in multiarch paths[1]. Thus, and perhaps for
additional reasons, multiarch is not yet of much benefit to
cross-compilation in Wheezy, at least not with the cross-compilers
from emdebian.org/debian.
Instead, those cross-compilers still require that foreign libraries be
installed via xapt, which generates -cross packages with, e.g.,
headers in /usr/arm-linux-gnueabi/include rather than the
multiarch-correct path /usr/lib/arm-linux-gnueabi.
The current plan is to create new cross-compilers which build from
source and can become citizens of the Debian archive itself, rather
than create additional cross-compilers via the old method. These new
cross-compilers, in addition to building from source, will find
foreign libraries which are installed in multiarch paths. They don't
exist now, however, and won't exist in time to be released in Debian
Wheezy.
Thibaut Girka worked on this during GSoC 2012, but that work is
incomplete in some way and the resulting cross-compilers were not put
into the emdebian.org/debian repos.
It's likely I've misunderstood some things, and boldly misstated them
above. Thank you in advance for putting the record straight.
-- Ryan
--
1. In some cases, the compiler gets a working library path anyhow via
pkg-config, but not necessarily a working header path.
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