deb: provide build-arch and build-indep targets

This is required by Debian Policy Manual section 4.9:

    https://www.debian.org/doc/debian-policy/ch-source.html#s-debianrules
These are needed for building and running on all platforms

(cherry picked from commit 3b03cefb49d964adaa9a83dc0f1775c4fdb97770)

Conflicts:
	debian/control.in
Fail on missing programs, instead of generating bogus scripts

(cherry picked from commit 0b5fba46aba7b35c8c3bcb80de43dec0ba8e97da)
Explicitly give the right build dependency for insmod/rmmod/etc

(cherry picked from commit 39e36ebd8fa5530ba87e162c17bac2c5ce57621f)

Conflicts:

	debian/configure
	debian/control.in
Merge remote-tracking branch 'origin/v2.5_branch' into 2.6

Conflicts:
	debian/configure (keep the 2.6 version)
	debian/control.in (keep the 2.6 version)
Merge remote-tracking branch 'origin/2.6'