[buildd-tools-devel] Fixed-up cross-build patches for 0.63

[Wookey]

After a small pause for xmas and a lot of faffing with git I've
finished merging rogers' sbuild-cross/cross-build with my working
stuff originally based on 0.62.6

This set of patches should apply without problems on that branch.

First patch solves the issue that I broke native builds (but in an
ugly way - a proper perl person could probably make that nicer).

The next 3 fix things and get to a version that seems to work nicely. 

The last 2 are attempting to be consistent about setting Host Arch and
Build Arch then using get throughout rather than get_conf. I hope
that's stylistically suitable. I left a few get_confs in
'run_chroot_session' in Build.pm, mostly for style, but also I wasn't
sure if that might break. That fn uses 'Host' for the Build chroot,
which is now confusing. Probabaly best to rename BuildChroot or
something. I've left it for now.

One thing I noticed that is odd on that branch: I have this little
diff against my old 0.62 working version rebased onto 0.63 master:
@@ -705,7 +704,7 @@ EOF
                if (defined($deps->{'Build Conflicts Arch'}) &&
                    $deps->{'Build Conflicts Arch'} ne "");
        }
-       if ($self->get_conf('BUILD_ARCH_ANY')) {
+       if ($self->get_conf('BUILD_ARCH_ALL')) {
            push(@positive_indep, $deps->{'Build Depends Indep'})
                if (defined($deps->{'Build Depends Indep'}) &&
                    $deps->{'Build Depends Indep'} ne "");

That differs from Roger's sbuild-cross/cross-build branch. I'm not
sure which is right...

I think that's all.