- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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