Support for cross-compilation by introducing variables in configure [patch in Debian bug tracking system]

[smoe]

The Debian folks cross-build for slower architectures/embedded systems, which may also be of interest for the more exotic CNC opportunities. Something like pkg-config only provides data on the host system, though. The short patch provided here is helping out:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1070025

This report shall serve as a reminder for now, will come up with a PR as time permits.