Enable hwloc with everything it implies

This commit enables hwloc support by addind build dependency to
libhwloc-dev. Unfortunately, upstream autotools macro that checks
for hwloc headers also adds rpath in LDFLAGS and this has the effect
to make lintian very very angry. That is why a new patch has been
added to fix the macro and avoid usage of rpath when --with-rpath
flag is not set. This patch, for being fruitful requires autoconf to
be run after being applied. It is the reason why autoreconf has been
enable in d/rules.

Easy, right?