Re: Word of Emdebian at LinuxWorld Exp (London) ?
Erik Andersen wrote:
Only wimps are afraid of cross-compiling :-)
Solvable, but speaking from the experience of having been
building cross-compiling toolchains and root filesystems for
uClibc targets for a few years now, it can involve a lot of work
and a lot of little gotcha. Even for packages that compile,
configure scripts have often tried to compile and execute stuff
for the target, and then silently include bunches of app bloating
workarounds.
Take a look at the openembedded project. A fine project, but
they have sure had to do a _lot_ of work to make configure
scripts cross compile well, and have eventually resorted to
simply stuffing pre-canned configure test results into their
build system....
Ah, yes, autoconf and cross-compiling are great fun. ptxdist
sets a bunch of 'standard' autoconf overrides in its environment,
but there are always more.
Every time I run into a package whose configure script
doesn't support cross-compiling well, e.g. which have
some AC_TRY_RUN tests whose values aren't cached such that
they can be overridden via the environment, I first curse
the gods, then send a patch to the maintainers so nobody
else has to deal with that kind of crap.
Yup. ptxdist is a derivitive of the uClibc buildroot system. We
talked about merging the projects at one point. So yes it is a
fine example. The openembedded project is also one to watch
closely. It is the next generation from kergoth and the other
openzaurus folk (where openzaurus itself was a next generation
derivitive of the tuxscreen buildroot, which is another uClibc
buildroot derivitive).
Hrm. I looked at openembedded.org a while ago, but it seemed like they
were still trying to figure out what sort of build system to use.
They even were considering SCons, which made me want to run
for the hills. (SCons is fine, if you have lots of RAM, and
don't mind every build system looking completely different,
and like Python. We use it at work, and it takes about 150 MB
of RAM and 90 seconds just to figure out what to build.)
There are of course plenty of build-everything-from-source
embedded and non-embedded distros out there. A fine example
of the breed is uClinux-dist
http://www.uclinux.org/pub/uClinux/dist/
which also includes a linux kernelconf menu based package
selection system (similar to ptxdist). But it supports a
much larger range of sytems (both mmu-full and mmu-less)
and includes a very nifty product specific support mechanism
that makes it easy to rebuild a wide range os things.
Erik, you've *got* to do better publicity for buildroot and uClinux-dist!
I'd never heard of uClinux-dist before, and
it took me a long time to stumble onto buildroot.
I spent quite a while trying to find little distros like that.
Time for another "here's a list of all the build-everything-from-source
embedded distros" post / web page, I guess.
- Dan
--
Dan Kegel
http://www.kegel.com
http://counter.li.org/cgi-bin/runscript/display-person.cgi?user=78045
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