Ah; libspice-*-dev are architecture: all packages since they don't require rebuilding for different archs (they're just headers being shipped), so they're available on i386 even if not meant to be used. We can fix the package to not build-depend on them.
Ah; libspice-*-dev are architecture: all packages since they don't require rebuilding for different archs (they're just headers being shipped), so they're available on i386 even if not meant to be used. We can fix the package to not build-depend on them.