When tearing down a TCP connection, try injecting a RST segment
by pretending to peer has received the last packet as an out of
the blue packet.

This allows the usage of
--ip_version=ipv4_mapped_ipv6
at the beginning of a script.

Ensure that
 0.00 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+1.00 close(3) = -1
      `echo Cleanup`
works

Ensure that
 0.00 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+1.00 close(3) = -1
is handled correctly.

The names of the constants were wrong and the code wasn't dealing
with the case that none of the constants are defined, like in
the case on PowerPC for FreeBSD.

This is ported from packetdrill 2.0.

This is from packetdrill 2.0 with the addition of support for
--define=PROTO=132

You can use -Dproto=IPPROTO_SCTP or --define proto=IPPROTO_SCTP
and run the script
```
 0.0 socket(..., SOCK_STREAM, proto) = 3
+0.0 close (3)
```
to control the protocol being used from the command line.

This avoids conflics with definitions on Solaris 10.4.

Remove the inclusion of netinet/sctp.h after enabling SCTP support
in platfroms.h.

The Solaris Studio compiler uses different flags...