During the GSoC 2012, Jesse Hagewood worked on text processing tools.
I have extracted from that summer of code the sdiff(1) part and tried to finish
it.
I have also imported the regression tests from NetBSD and modified them match
what the GNU version is really producing
Compared to the summer of code, I have fixed the z version of sdiff
Finished fixing the "column" output vs gnu diff (which makes it different from
OpenBSD and NetBSD)
Added the '(' that gnu sdiff shows when only printing the left column
The last difference with GNU sdiff that I do not plan to fix the fact that this
version padds using spaces while GNU sdiff pads using tabs (I honnestly prefer
the current behaviour and visually there is no differences)
Tested and compared against gnu sdiff as in base