Allow ipv6 for migration

Hi

v2:
- create socket_set_reuseaddr() to have it different for Windows and everything else (Peter Maydell)
- use strerror() instead of perror (Peter Maydell)
- fprintf(): one of them removed, the other one ...
it is complicated, would have to return two errors: getaddrinfo one and normal errno. Not feasible IMHO until we integrate all other users of getaddrinfo() and think of a nice API.

v1.

1st patch moves migration to use getaddrinfo() instead of parse_host_port(). This allows us to use ipv6 addresses. As an extra bonus, now we can use names from /etc/services.

Code for net_socket_listen_init() and net_socket_connect_init() was almost identical to migration one, so also changed that ones. The difference were small based on how error codes were handled. After discussing with Anthony, it appears that the right ones are the migration ones.

Tested (the migration code) with:
- "tcp:foo:4444" ipv4 name
- "tcp:foo6:4444" ipv6 name
- "tcp:0:4444"
- "tcp:foo6:iqobject" (this was an unused entry on my machine /etc/services)
iqobject 48619/tcp # iqobject
- "tcp::4444": let the kernel make a choice

Please review.

Later, Juan.

Juan Quintela (3):
create socket_set_reuseaddr()
Use getaddrinfo for migration
net/socket: allow ipv6 for net_socket_listen_init and
net_socket_connect_init

 gdbstub.c          |    6 +--
 migration-tcp.c    |   53 ++++++-------------------
 nbd.c              |    5 +--
 net.c              |  106 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 net/socket.c       |   66 ++++++--------------------------
 os-posix.c         |    1 +
 oslib-posix.c      |    8 ++++
 oslib-win32.c      |    6 +++
 qemu-sockets.c     |    6 +-
 qemu_socket.h      |    4 ++
 tests/linux-test.c |    4 +-
 11 files changed, 158 insertions(+), 107 deletions(-)

1.7.4