bsd's ifconf conflicts with osv's; rename it.

We use the bsd version in <osv/ioctl.h>, since we currently don't support
the Linux-ABI variants of these ioctls.

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>
Tested-By: Benoit Canet <benoit@irqsave.net>

  1. Netperf patch removed from repository
  2. Documentation updated

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>

This allows lazy people like me to just copy the instructions

1. it is much cleaner that the header files perform extern "C" themselves,
   so they can be included both from C and C++ code.

2. when doing extern "C" from a C++ file then __cplusplus is also defined,
   and compilation can break in some situations.

3. as a bonus, this patch increase compilation time.

ifconfig used to call sofree(), which assumed accept_mtx was taken, which
wasn't true, resulting in either an assertion failure (if we implement
assert_mtx - see next patch) or a mutex corruption (if assert_mtx does
nothing).

Instead, we should call soclose(). This wasn't very hard to figure out,
given the comment in socreate() saying "The socket should be closed with
soclose()." :-)