Architecture field based on another package Architecture field

[Ghislain Vaillant <ghisvail@gmail.com>]

Dear all,

I have a package (nfft) which builds a few binary packages. These binary 
packages correspond to a build of the same library but for different 
floating precisions (single, double, long-double).

For the long-double build, nfft requires the long-double version of fftw 
which is not available for all architectures. Since the other
precisions are not affected, only the long-double version of the library 
should have a restricted set of architectures via the Architecture field 
in d/control.

Is there a way to simply tell the Architecture field of this binary 
package (libnfft3-long2) that it should use the same architectures as 
the libfftw3-long3 ? Something like:

Architecture: ${libfftw3-long3:Architecture}

maybe?

Or do I need to list them all manually?

Same question for d/rules, can I somehow query all the architectures 
supported by libfftw3-long3 during the build (via dpkg?), so I can use 
this list to restrict the build process of the long-double precision.

Many thanks,
Ghis