Re: [xml] (Broken) multi-arch support in xml2-config

[Daniel Veillard <veillard redhat com>]

On Wed, Nov 07, 2012 at 03:49:47PM -0500, Daniel Richard G. wrote:
> I noticed that this bit was added about a month ago to xml2-config.in:
>
>       if [ "`ldd /bin/sh | grep lib64`" = "" ]
>       then
>           libdir=${exec_prefix}/lib
>       else
>           libdir=${exec_prefix}/lib64
>       fi
>
> This caused a subsequent build of LibXSLT to fail, because the
> needed library was under $prefix/lib/, and the build system was
> looking under $prefix/lib64/.
>
> I'm not seeing why this code is there.

  Because I had that patch for years and years on Fedora and RHEL builds
and it was looking to me that this should not be a problem for others.
Apparently it is :-\

> There are multiple problems
> with this approach:
>
> * Custom libdir values specified at configure time (i.e. --libdir=blah)
>   are ignored in favor of the common-case default
>
> * The lib64 subdir, if returned, is returned solely based on how /bin/sh
>   is linked---rather than whether "make install" actually puts the library
>   there or not
>
> * As written, there isn't even a way to request an architecture explicitly
>   if more than one is installed (something like --lib32/--lib64 options or
>   similar)
>
> * "lib" versus "lib64" isn't the only possible distinction, either; my
>   64-bit Ubuntu system, for example, has /usr/lib/ and /usr/lib32/.
>
> * The "foo-config" script mechanism, to the degree that it can work in a
>   multi-arch scenario, works a lot more cleanly when you have one instance
>   of the script per architecture (rather than one script handling multiple
>   architectures). All I would do then is set my PATH appropriately, e.g.
>
>       PATH=/usr/arch/x86_64-linux-gnu/bin:/usr/bin
>
>   or
>
>       PATH=/usr/arch/i386-linux-gnu/bin:/usr/bin
>
>   when LibXML2 is installed for both amd64 and i386 under /usr/arch/.
>
>
> What was the motivation for trying to shoehorn multi-arch support
> into xml2-config?

  Avoid keeping a distro specific patch, assuming it would work
elsewhere. What is your suggestion, removal or fixing ?

Daniel

-- 
Daniel Veillard      | Open Source and Standards, Red Hat
veillard redhat com  | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
http://veillard.com/ | virtualization library  http://libvirt.org/