MFC r292337, r292552, r292553:

Build mount_smbfs for arm. Also sort the subdirs.

Avoid unaligned memory accesses when encoding netbios names in libsmb.

The current code for encoding a netbios name converts each byte to a 16-bit
value and stores the result by casting a char* to u_short*, resulting in
alignment faults on strict-alignment platforms.

This change reimplements the encoding routine using only byte accesses to
memory. There is no particular reason to work with 16-bit values just
because the encoding process creates two bytes of output for every byte of
input. Working a byte at at time also avoids endian problems for big-endian
platforms.

Make the building of libsmb and mount_smbfs unconditional, now that r292552
has eliminated alignment and endian problems that were making it fail on
some platforms.

PR: 180438
PR: 189415
Relnotes: Yes

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

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

- Trim an unused and bogus Makefile for mount_smbfs.
- Reconnect with some minor modifications, in particular now selsocket()
internals are adapted to use sbintime units after recent'ish calloutng
switch.

Disconnect non-MPSAFE SMBFS from the build in preparation for dropping
GIANT from VFS. In addition, disconnect also netsmb, which is a base
requirement for SMBFS.

In the while SMBFS regular users can use FUSE interface and smbnetfs
port to work with their SMBFS partitions.

Also, there are ongoing efforts by vendor to support in-kernel smbfs,
so there are good chances that it will get relinked once properly locked.

This is not targeted for MFC.

Merge from tbemd: use Makefile.arch to control building.

Reviewed by: arch@ (many times, no objection)