diff: add --word-diff option that generalizes --color-words

This teaches the --color-words engine a more general interface that
supports two new modes:

* --word-diff=plain, inspired by the 'wdiff' utility (most similar to
  'wdiff -n <old> <new>'): uses delimiters [-removed-] and {+added+}

* --word-diff=porcelain, which generates an ad-hoc machine readable
  format:
  - each diff unit is prefixed by [-+ ] and terminated by newline as
    in unified diff
  - newlines in the input are output as a line consisting only of a
    tilde '~'

Both of these formats still support color if it is enabled, using it
to highlight the differences.  --color-words becomes a synonym for
--word-diff=color, which is the color-only format.  Also adds some
compatibility/convenience options.

Thanks to Junio C Hamano and Miles Bader for good ideas.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/color.h b/color.h
index 5c264b0ce3..03ca064748 100644
--- a/color.h
+++ b/color.h
@@ -61,6 +61,5 @@ __attribute__((format (printf, 3, 4)))
 int color_fprintf(FILE *fp, const char *color, const char *fmt, ...);
 __attribute__((format (printf, 3, 4)))
 int color_fprintf_ln(FILE *fp, const char *color, const char *fmt, ...);
-int color_fwrite_lines(FILE *fp, const char *color, size_t count, const char *buf);
 
 #endif /* COLOR_H */