Extend mosh and mosh-server to support parsing a high port from
the desired_port argument.  The first (low) port must not be
greater than the second (high) port.
If only one value is provided, behaviour is as before; bind
to one port.  Also tweak the formatting in mosh-server(1) synopsis
to be consistent.

This resolves mosh issue # 296.

Signed-off-by: Luke Mewburn <luke@mewburn.net>

This reverts commit 0909ea55.

On FreeBSD, the socket option length must be declared as an int.

While I'm here, translate dscp (0x92) to the appropriate constants.

(tested on FreeBSD only so far)

... plus the local changes from:

  3b2604b8 Handle early gcc compilers that are missing __builtin_bswap64 or __builtin_ctz
  e8236c5f Use AlignedBuffer stedda posix_memalign(). Should work on PPC OS X 10.5.
  9827d123 Switch to OpenSSL AES

Closes #331

(One is silver and the other gold...)

Return if pw is NULL, to avoid dereferencing it at pw->pw_dir.

Avoid playing games with network-layer timestamps.

This reverts commit dce0c7f8.

Signed-off-by: Timo Sirainen <tss@iki.fi>

Otherwise the next opened fds are 0/1/2, and any code writing to
stdout/stderr might break things by writing to an unintentional fd.

Signed-off-by: Timo Sirainen <tss@iki.fi>

Signed-off-by: Timo Sirainen <tss@iki.fi>