Inert DEB_BUILD_OPTIONS noopt in debian/rules files

[Guillem Jover <guillem@debian.org>]

Hi!

While going through the dpkg codebase, I realized that any
debian/rules file that calls dpkg-buildflags through make's $(shell)
function will not honor at least noopt from DEB_BUILD_OPTIONS, which
affects the build flags returned by dpkg-buildflags.

This is fixed in dpkg 1.17.14 buildflags.mk, but any package handling
the flags inline will probably be affected, as I don't expect that case
to be currently handled.

Packages using dh(1) or cdbs are not affected. I'm not sure how many
packages might be affected, but I think the current situation is *bad*.

Regards,
Guillem