tuxpuck cross builds successfully for a number of architectures. It
fails for e.g. arm64. That is an architecture that has gained
architecture-specific compiler flags such as
-mbranch-protection=standard. tuxpuck has some compiler invocations for
the build architecture compiler, but does not yet distinguish between
build architecture flags and host architecture flags. Hence, the build
architecture compiler invocation can fail. I'm attaching a patch that
applies the *_FOR_BUILD concept to more variables. debhelper already
passes them all, so the buildsystem change is enough to make it cross
build for more architectures.

Helmut