This matches GNU diff(1) behavior and, more importantly, eliminates any
source of confusion if multiple formatting options are specified.
Note that the committed diff differs slightly from the submitted: I've
modified it so that we initialize diff_format to something that isn't an
accepted format option so that we can also reject --normal -c and -c
--normal, which would've otherwise been accepted because the default was
--normal. After option parsing we default it to D_NORMAL if it's still
unset.
PR: 243975
Submitted by: fehmi noyan isi
MFC after: 1 week
As noted by cem in r338035, coccinelle invokes diff(1) with the -B flag.
This was not previously implemented here, so one was forced to create a link
for GNU diff to /usr/local/bin/diff
Implement the -B flag and add some primitive tests for it. It is implemented
in the same fashion that -I is implemented; each chunk's lines are scanned,
and if a non-blank line is encountered then the chunk will be output.
Otherwise, it's skipped.
MFC after: 2 weeks
etcupdate(8) requires that option, while GNU diff supports many more variation
of that options, their behaviour beside the simple verion implemented here are
quite inconsistent as such I do not plan to implement those.
The only special keyword supported by this implementation are: %< and %>
%= is not implemented as the documentation of GNU diff says: common lines, but
it actually when tested print the changes from the first file
Some of the modifications from the previous summer of code has been integrated
Modification for compatibility with GNU diff output has been added
Main difference with OpenBSD:
Implement multiple GNU diff options:
* --ignore-file-name-case
* --no-ignore-file-name-case
* --normal
* --tabsize
* --strip-trailing-cr
Make diff -p compatible with GNU diff
Implement diff -l
Make diff -r compatible with GNU diff
Capsicumize diffing 2 regular files
Add a simple test suite
Approved by: AsiaBSDcon devsummit
Obtained from: OpenBSD, GSoC
Relnotes: yes
