prometheus-ipmi-exporter fails to cross build from source. On the
surface it fails running the host's Go compiler. Since gccgo became
unsupported, we can change it to golang-go and since the golang
implementation is multitarget we can annotate it :native.

At this point, we get an ipmi_exporter executable, but moving it around
fails, because cross compilation uses a different directory hierarchy
below the _build folder. I suggest renaming the file after
dh_auto_install where the path becomes predictable.

Last but not least, the manual page generation wants to run it and we
cannot do that. I suggest adding a native build pass. Due to the
different layout, we can reuse the same build directory.

Please consider applying the attached patch.

Helmut