Re: AW: Build of powerpcspe port
On Thu, Mar 17, 2011 at 05:32:34PM +0100, David Kuehling wrote:
> > Just for better understanding: could you please outline some technical
> > reasons why - Debian packages do not reliably build from a
> > cross-compile environment
>
> Many complex software packages make assumptions that are incompatible
> with cross-compilation. such as: programs compiled in the build process
> can be executed during the build process. Autoconf makes it even worse,
> since many autoconf feature detection macros use that assumption and
> fail during cross-compilatio.
These are valid issues. It's possible to overcome them if you can read
configure (which is written in Bourne shell) and have a (kernel + libc
+) shell on the target. In my experience, there are still many packages
that have relatively complex hierarchical Makefiles and no provisions
for cross-compilation at all. Just a couple of days ago I found it
faster to move a package to autotools to get it cross-compiled, rather
than trying to hack its Makefile.
> > - crossbuild of Debian packages requires the "official" Debian-built
> > cross-compiler?
>
> No, it needs an official cross-compiling version of dpkg-buildpackage.
> Also, naturally it then also needs a whole bunch of target system
> libraries installed at some 'sysroot' directory.
You can bootstrap something with a random suitable toolchain. But you
want to build Debian packages, which have to be compatible with its
glibc, which is, AFAIK, in some way hard-coded into your toolchain.
There is some cross-compilation work done in SLIND and Crush, although I
don't know whether they are usable OOTB as provided on public web sites.
With kind regards,
Baurzhan.
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