Moving 32-bit libraries to (/usr)/lib32 on amd64

[Aurelien Jarno <aurelien@aurel32.net>]

Hi all,

The amd64 port is currently providing 32-bit libraries via the ia32-libs
package. This package was originally designed for ia64, and thus install
32-bit libraries in /emul/ia32-linux/ . This is not compliant with the
FHS for amd64. Note also that this package does not rebuild the
libraries, but use the ones in the i386 packages.

As it has already been discussed with Steve Langasek on IRC (see
bug#274367 for a log), we should move those libraries to (/usr)/lib32.
This is still not FHS compliant, but a it is more "standard" library,
and it is the solution choosen by other distributions like Gentoo or
Ubuntu. I think we should also build them from the corresponding source
packages.

The first part of the transition need some coordination between a few
packages. The idea behing this transition, is that we keep libraries in
/emul/ia32-linux/ until they are transitioned. It is even possible to
keep two versions of the libraries (one in /usr/lib32, the other in
/emul/ia32-linux/) for a while to reduce the number of upload of
ia32-libs, which is quite a big package.

Here is my view on the transition:
1) Upload of glibc with 32-bit libraries
2) Upload of ia32-libs without the /usr/lib32 symlink, and without the
   glibc for amd64
3) Upload of zlib with 32-bit libraries in /usr/lib32 instead of
   /emul/ia32-linux/
4) Upload of gcc-4.0 with 32-bit libraries in /usr/lib32 instead of
   /emul/ia32-linux/

The order has been defined to reduce the number of uninstallable
packages on amd64. Only between step 1 and 2, the new packages
libc6-i386 and libc6-dev-i386 are uninstallable. It also permit to do
the transition without needing to bootstrap one or more packages, which
may be difficult on amd64, as only very few people have the rights to
upload packages.

I have already patches for all those packages, I have put them on
http://people.debian.org/~aurel32/amd64-lib32

Then it would be possible to transition the remaining packages, but no
more coordination is need.

I am waiting for you comments, especially if you think about something I
have forgotten, and also for the opinion of the release team.

Bye,
Aurelien

-- 
  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   aurel32@debian.org         | aurelien@aurel32.net
   `-    people.debian.org/~aurel32 | www.aurel32.net