Hi everyone,
I am currently working on packaging 2 libraries (potentially a 3rd one too) which supports multi-precision arithmetic (single, double and long double), similar to what FFTW does. So from the source package, one can build different binary package corresponding to each precision. For each precision, the configure flags and library suffix need to be changed to produce each version of the library with non-clashing names. Since, the source package uses autotools, this can be achieved with dh-autoreconf I suppose.
I could take a similar d/rules as in FFTW but it looks quite dated. I am sure the package build process could be somewhat modernized and simplified using dh commands and overrides. However, I am not sure which approach would be possible or best.