Cross-building with Debian
Note: this documentation is fairly old, and is probably out-of-date. I haven't needed to cross-build a Debian package in a long time.
This was a pain. I needed to do it for ncompress because the autobuilders don't build for non-free, and nothing moves from unstable to testing unless it builds on all of the arches it's currently available for. Solution? Build for as many as possible by hand, and then ask ftp-master to remove the ones that can't be built.
How do I build? Two ways - either look for a machine that runs sid or look for a machine that runs woody but is listed as (+chroot):
http://db.debian.org/machines.cgi
I used the following machines:
alpha escher.debian.org chroot arm debussy.debian.org chroot hppa paer.debian.org sid (but use chroot) ia64 merulo.debian.org chroot mips casals.debian.org chroot powerpc voltaire.debian.org sid (but use chroot) s390 trex.debian.org chroot sparc vore.debian.org chroot m68k crest.debian.org chroot
To get into a chroot on a machine that has one, you use:
dchroot unstable
You could also use stable, oldstable, etc. as needed. I've updated my ~/.profile to put the name of the chroot environment in the prompt. I got this from /etc/debian_chroot.
Since the .dsc and .orig.tar.gz files have already (presumably) been uploaded by the i386 build, you can't upload them again. You can only make this work with the -b option to dpkg-buildpackage. Also, it's not a good idea to have your secret key on a machine you don't control - so, you should be taking the changes file back home and signing it by hand.
dpkg-buildpackage -b -uc -us -rfakeroot -i gpg --clearsign <changefile>
When I download everything (the build files and everything) then these three steps accomplish the signing and leave me just the files I need to upload.
gpg --clearsign *.changes mv *.asc *.changes rm *.diff.gz *.orig.tar.gz
It's not too bad. Using an autobuilder would be nicer, though. 