Depencencies of gcc on glibc/eglibc and libc6-i386

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

I would like to better understand the depencencies between the various
gcc packages and libc6{,-i386}, in particular as they relate to the
transition to /lib32.

In debian/rules.conf we have:

libc_ver := 2.5
ifneq (,$(findstring gnat,$(PKGSOURCE)))
  libc_ver := 2.9-21
endif

This variable generates the Build-Depends line in debian/control:

Build-Depends: glibc (>= 2.9-21), ...
or
Build-Depends: glibc (>= 2.5), ...

Then we have, also in debian/rules.conf:

echo 'confl:lib32=libc6-i386 (<< 2.9-22)' >> debian/substvars.local.tmp

which generates the run-time (rather install-time) conflicts for all
packages.

I am wondering why there are two different versions of libc6-i386
listed.  What happens when building gcc (not gnat) on a machine that has
glibc (= 2.5) and libc6-i386 (= 2.5) installed?  Will it even work?  If
so, I gather that the library packages will automatically get their
shlibs:Depends set to glibc (>= 2.5), libc6-i386 (>= 2.5), reaching
dependencies like:

Build-Depends: glibc (>= 2.5), ...
Depends: glibc (>= 2.5), libc6-i386 (>= 2.5), ...
Conflicts: libc6-i386 (<< 2.9-22)

How about unifying all the version numbers to 2.9-22?

-- 
Ludovic Brenta.