Import sdiff(1) from the diff version written by Raymond Lai,
improved during GSoC 2012 by Jesse Hagewood.

Compared to the version done in during that summer of code:
- Remove the zlib frontend: zsdiff
- Compatible output (column size and separators) with GNU sdiff

Compared to GNU sdiff in ports:
- The only difference is padding using spaces vs tabs

Compared to OpenBSD and NetBSD import:
- Implement missing options (including long options) from GNU sdiff
- Improved support for the edition mode (signal handling)
- Output visually compatible with GNU sdiff: size of columns

While here import regression tests from NetBSD adapted to fit the output as
expected by GNU sdiff

Reviewed by:	emaste (in part)
Obtained from:	OpenBSD, NetBSD, GSoC 2012
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D5981
Differential Revision:	https://reviews.freebsd.org/D6032 (diff with NetBSD version)
Differential Revision:	https://reviews.freebsd.org/D6033 (diff with OpenBSD version)

These are no longer needed after the recent 'beforebuild: depend' changes
and hooking DIRDEPS_BUILD into a subset of FAST_DEPEND which supports
skipping 'make depend'.

Sponsored by:	EMC / Isilon Storage Division

Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.

Still need to add real targets under targets/ to build packages.

Differential Revision:       D2796
Reviewed by: brooks imp

Requested by: Simon Gerraty <sjg@juniper.net>

is to be provided by --suffix).  Looking at the usage here in diffutils,
it seems that we can just get rid of the -b .orig stuff.  This resolves
a problem that can triggered if we move toward to a more permissively
licensed patch(1) program.