Re: cross compiling on x86_64

[Philippe A.]

2007/2/25, Sam Varshavchik <mrsam(a)courier-mta.com&gt;:
>  Philippe A. writes:
>
>  > « HTML content follows »
>  > I have installed FC6 x86_64 on my new system. I would like to know how I
>  > can compile a 32 bit freetype package. The following didn't work:
>  >
>  > rpmbuild -bb freetype.spec -bb --target i386
>  >
>  > It fails with these errors:
>  >
>  > checking build system type... x86_64-redhat-linux-gnu
>  > checking host system type... x86_64-redhat-linux-gnu
>  > checking target system type... i386-redhat-linux-gnu
>
>  I do not believe that rpm's stock configuration supports cross-building to
>  a
>  different architecture.  The --target parameter only sets the architecture
>  label on the resulting rpms, and not much more.
>
>  Cross-compilation is not trivial to set up.  You must install, beforehand,
>  the i386 build of every library that your software compiles against, and
>  you
>  must know, beforehand, what they are.  Then, you'll need to arrange,
>  somehow, for the software's configuration script and makefile pass the
>  -m32
>  option to gcc.
>
>  It's rather unlikely that freetype's rpm and configure script implements
>  all
>  of this. 

Well when you install FC x86_64 you get all these 32 bit libs installed. If
you rpm -qa you get a lot of lib packages in double. One is 32 bit, one is
64 bit.

rpm -qa --queryformat "%{name}-%{version}-%{release}.%{arch}\n"

zlib-1.2.3-3.i386
zlib-1.2.3-3.x86_64

So that obviously mean they have been compiled. Since I cannot find a
separate SRPM for 32 bit and 64 bit, I have to assume the same was used.

I have found extra bits information here:

http://www.redhat.com/magazine/009jul05/features/multilib/

It's a nice article but not nearly technical.

Someone suggested the following to me. That didn't work.

setarch i386 rpmbuild -bb --target i386 freetype.spec

I don't see how mock can help solve this issue. It seems to be oriented
towards spec file verification.

http://fedoraproject.org/wiki/Extras/MockTricks

I keep looking. If anyone else got a suggestion, thanks for letting me know!

If you think about it, it would be insane to package a distro with different
sets of rpms. So there has to be a solution that's not so crazy. Maybe
recompiling gcc? I seem to have seen some hints to that effect but haven't
investigated further yet.