arch-specific packages and the new SCC requirements

[Thomas Bushnell BSG <tb@becket.net>]

To be in SCC, under the proposal we're all discussing, an arch must
have build 50% of the archive, not counting arch-specific packages.

The Debian Hurd project has another category that should be excluded
because they are kernel-specific.  (The current list on the web page
is update, makedev, ld.so, modconf, modutils, netbase, pcmcia-cs,
procps, ppp, pppconfig, setserial.  There are surely more.)

Ideally we would have a new field in the control file to specify
Kernel (or System), which would normally be "any", but for packages
like these would be "linux".  But that's a hornets nest of potential
problems.

We could ask the maintainer of update (say) to change it from
"Architecture: any" to "Architecture: i386 mk68 ...".  But that's
tedious, brittle, and we all hate it.

What would really win, of course, is "Architecture: !hurd-i386".  But
negative declarations are currently not yet supported.  They should
be.

None of this is insoluble, and I assume that it won't be a serious
problem taking account of it, but it does mean that applying the 50%
and 90% threshholds will require more than simply looking at
statistics and applying them, because we don't currently have a
fully-robust way to indicate the relevant kind of "arch specific".

Thomas