build: fail in configure on missing dependency with --enable-bpf-compiler

The build of utils/nfbpf_compile depends on libpcap. If configure is
run with --enable-bpf-compiler, the script succeeds, but make fails.

This small patch adds a test for the dependency (libpcap) in configure
and fails hard if not found.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
1 file changed