slink->potato upgrade fail

[Fumitoshi UKAI <ukai@debian.or.jp>]

Package: gcc
Version: 1:2.95.2-8
Severity: grave

Hi,
In IRC channel #debianjp (talked in Japanese), we are reported
that upgrading from slink to potato will fail with:
 libc6-dev: Dedpends: libc6 (= 2.0.7....) but 2.1.3-8 is installed

According to our investigation, this is because

egcc and g++ installed
 Package: egcc
 Version: 2.91.66-0slink2
 Depends: libc6, g++ (>= 2.91.66), g++ (<< 2.91.67)

 Package: g++
 Version: 2.91.66-0slink2
 Depends: libc6, binutils (>= 2.9.1), libstdc++2.9-dev (>= 2.91.66)

 Package: libstdc++2.9-dev
 Version: 2.91.66-0slink2
 Depends: libstdc++2.9 (>= 2.91.66), libc6-dev, g++ (>= 2.91.58)

then, these will require libstdc++2.9-dev.  
Since pototo doesn't have libstdc++2.9-dev (but libstdc++2.10-dev),
however, apt-get will insist with libstdc++2.9-dev because no egcc
in potato.  (I don't know why apt-get do this way)

It might be apt-get bug, but it could be fixed by changing dependency
of gcc package in potato to conflicts with egcc *without* versioned 
dependency, that is, 

 Package: gcc
 Depends: libc6 (>= 2.1.2), cpp (>= 1:2.95.2-4), cpp (<< 1:2.95.3), binutils (>= 2.9.5.0.12)
 Recommends: libc-dev
 Suggests: gcc-doc (>= 1:2.95.2-4)
 Conflicts: libc5-dev, egcc
 Provides: egcc, c-compiler
 Replaces: egcc

In our case, upgrading works fine once egcc is removed, so it is one easy
solution of this problem.  And we have egcc anymore, so I think it is no 
necessary to conflicts with egcc with versioned.

Any other good solution?

Thanks,
Fumitoshi UKAI