Bug#476530: control field to tell that cross-building is not possible
There are some sporadic bug reports around like #315935 that basically say
that the package cannot be cross-compiled. I think it would be useful to have
a control field that told dpkg-buildpackage that cross-compiling won't work
for the package in question. (dpkg-buildpackage uses the Architecture field
to see whether the package will build for a given architecture, so this would
be quite similar.) Or maybe another way to convey this information would be
better, but I think this ought to be recorded somewhere so that the
cross-building folk don't waste their resources.
Policy isn't entirely clear. Section 4.9 mentions the DEB_*_ARCH variables,
but it is not clear whether their use is mandated. In bug #315935, it is
opined that cross-build support isn't mandatory, which is of course the
practical reality anyway.