netlink: use SOCK_CLOEXEC when creating socket file descriptors
netlink: use SOCK_CLOEXEC when creating socket file descriptors

Use SOCK_CLOEXEC when calling socket(2). This avoids races between
one goroutine calling socket(2) and another performing fork + exec,
which could otherwise result in the child process inheriting an
unexpected netlink socket file descriptor.

Fixes #137.

Signed-off-by: Andrei Tudor Călin <1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e@acln.ro>

mdlayher/netlink