All our C sources should include <nft.h> as first. This prepares an
environment of things that we expect to have available in all our C
sources (and indirectly in our internal header files, because internal
header files are always indirectly from a C source).
Signed-off-by: Thomas Haller <thaller@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>