'RELENG_5_3_0_RELEASE'.

This commit was manufactured to restore the state of the 5.3-RELEASE image.

1) Avoid shadowing index.
2) Constness.
3) Missing prototype for ifcmd.
4) Missing include of string.h.
5) Avoid shadowing error function.
6) ANSI definition for main.

with namelists. use __FBSDID().

_POSIX2_LINE_MAX as required.
While being there, wrap an overly long line.

MFC after:	3 days

and compiler warnings.
The data for network statistics are still obtained via the kvm interface
if systat was started with the needed privileges, otherwise sysctls are
used. The reason for this is that with really many open sockets, the
sysctl method is probably slower, but it systat -netstat is probably not
really usable in either mode under these conditions.

Approved by:	rwatson

  base system, but not in BruceBSD.
o Fix up style violations of various sorts.
o Remove redundant normalization of hertz variable, as the sysctl handler
  does this work (unlike when kread was used).

Submitted by:	bde

  using kmem.