Add defines, enums and headers for MSVC

Add defines needed to compile netlink-socket.c and netlink.c.

Add a wrapper and the functionality behind it for syconf.

Add the newly created files to the noinst_HEADERS in windows/automake.mk

Signed-off-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
netlink-protocol: Add more definitions.

Add MAX_LINKS define needed for nl_pool.

Add NLM_F_CREATE and NLM_F_EXCL defines also.

Signed-off-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
netlink-socket: Allow compiling on MSVC even without HAVE_NETLINK.

Bypass the error compilation when compiling under MSVC.

Signed-off-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
netlink-socket: Adapt to Windows and MSVC.

Add two functions set_sock_pid_in_kernel and portid_next. This will allow
the channel identification for the kernel extension to send back messages.

Replace send with WriteFile equivalent and ignore nl_sock_drain for the moment
under MSVC.

Replace sendmsg and recvmsg with ReadFile and WriteFile equivalents.

On MSVC put in handle instead of fd(sock->fd becomes sock->handle).

Creation of the netlink socket will be replaced by CreateFile equivalent.

Add MAX_STACK_LENGTH for MSVC.  This will be our maximum size for on-stack
copy buffer.

Signed-off-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Add more files to the openvswitch library on MSVC

Add netlink related files to the windows build.

Signed-off-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
tests: Add another test for extended registers.

ONF-JIRA: EXT-244
Suggested-by: Jean Tourrilhes <jt@hpl.hp.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jean Tourrilhes <jt@hpl.hp.com>