The `ethercat_config.hpp` header was included from `ethercat.hpp`
after opening the `villas::node` namespace. This made all definitions
originating from that header including the transitive definitions
from ethercat's `ecrt.h` part of the `villas::node` namespace.
The especially problematic part was that `ecrt.h` itself has an
`#include <netinet/in.h>` introduced in [1]. This caused the libc
definitions for `sa_familt_t`, `sockaddr_in` and `sockaddr_in6` to be
moved into the `villas::node` namespace, causing build error on recent
`ethercat` versions.
[1]: c2f9baf96a
Signed-off-by: Philipp Jungkamp <philipp.jungkamp@rwth-aachen.de>
