Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Use thr_once() with once_t controls to initialize various thread_key_t
objects used to provide per-thread storage in the RPC code. Almost all
of these used double-checking with a dedicated mutex (tsd_lock) to do this
before. However, that is not always safe with more relaxed memory orders.
There were also other bugs, such as one in __rpc_createrr() that caused a
new key to be allocated each time __rpc_createrr() was invoked.

PR: threads/144558
Reported by: Sam Robb samrobb of averesystems com (key leak)
MFC after: 1 week

Add an implementation of the RPCSEC_GSS authentication protocol for RPC. This
is based on an old implementation from the University of Michigan with lots of
changes and fixes by me and the addition of a Solaris-compatible API.

Sponsored by: Isilon Systems
Reviewed by: alfred

Some libc symbol map cleanups.

net: endhostdnsent is named _endhostdnsent and is
private to netdb family of functions.

posix1e: acl_size.c has been never compiled in,
so there's no "acl_size".

rpc: "getnetid" is a static function.

stdtime: "gtime" is #ifdef'ed out in the source.

some symbols are specific only to some architectures,
e.g., ___tls_get_addr is only defined on i386.

__htonl, __htons, __ntohl and __ntohs are no longer
functions, they are now (internal) defines in
<machine/endian.h>.

Submitted by: ru

Use C comments since we now preprocess these files with CPP.

Add symbol maps and initial symbol version definitions to libc.

Reviewed by: davidxu