Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

- Remove unused sysvec variables from various syscalls.conf.
- Send the systrace_args files for all the compat ABIs to /dev/null for
now. Right now makesyscalls.sh generates a file with a hardcoded
function name, so it wouldn't work for any of the ABIs anyway. Probably
the function name should be configurable via a 'systracename' variable
and the functions should be stored in a function pointer in the sysvec
structure.

GC unused 'syshide' override to /dev/null. This was here to disable
the output of the namespc column. Its functionality was removed some time
ago, but the overrides and the namespc column remained.

$Id$ -> $FreeBSD$

Emulator KLD for SysVR4 executables grabbed from NetBSD.
See http://www.freebsd.org/~newton/freebsd-svr4 for limitations,
capabilities, history and TO-DO list.