Merge branch 'nd/diff-parseopt-2'

Second batch to teach the diff machinery to use the parse-options
API.

* nd/diff-parseopt-2: (21 commits)
  diff-parseopt: convert --ignore-some-changes
  diff-parseopt: convert --[no-]minimal
  diff-parseopt: convert --relative
  diff-parseopt: convert --no-renames|--[no--rename-empty
  diff-parseopt: convert --find-copies-harder
  diff-parseopt: convert -C|--find-copies
  diff-parseopt: convert -D|--irreversible-delete
  diff-parseopt: convert -M|--find-renames
  diff-parseopt: convert -B|--break-rewrites
  diff-parseopt: convert --output-*
  diff-parseopt: convert --[no-]compact-summary
  diff-parseopt: convert --stat*
  diff-parseopt: convert -s|--no-patch
  diff-parseopt: convert --name-status
  diff-parseopt: convert --name-only
  diff-parseopt: convert --patch-with-stat
  diff-parseopt: convert --summary
  diff-parseopt: convert --check
  diff-parseopt: convert --dirstat and friends
  diff-parseopt: convert --numstat and --shortstat
  ...

Documentation/diff-options.txt

@@ -41,6 +41,16 @@ ifndef::git-format-patch[]
 	Implies `-p`.
 endif::git-format-patch[]
 
+--output=<file>::
+	Output to a specific file instead of stdout.
+
+--output-indicator-new=<char>::
+--output-indicator-old=<char>::
+--output-indicator-context=<char>::
+	Specify the character used to indicate new, old or context
+	lines in the generated patch. Normally they are '+', '-' and
+	' ' respectively.
+
 ifndef::git-format-patch[]
 --raw::
 ifndef::git-log[]
@@ -148,6 +158,7 @@ These parameters can also be set individually with `--stat-width=<width>`,
 	number of modified files, as well as number of added and deleted
 	lines.
 
+-X[<param1,param2,...>]::
 --dirstat[=<param1,param2,...>]::
 	Output the distribution of relative amount of changes for each
 	sub-directory. The behavior of `--dirstat` can be customized by
@@ -192,6 +203,12 @@ directories with less than 10% of the total amount of changed files,
 and accumulating child directory counts in the parent directories:
 `--dirstat=files,10,cumulative`.
 
+--cumulative::
+	Synonym for --dirstat=cumulative
+
+--dirstat-by-file[=<param1,param2>...]::
+	Synonym for --dirstat=files,param1,param2...
+
 --summary::
 	Output a condensed summary of extended header information
 	such as creations, renames and mode changes.
@@ -386,6 +403,9 @@ endif::git-format-patch[]
 	Turn off rename detection, even when the configuration
 	file gives the default to do so.
 
+--[no-]rename-empty::
+	Whether to use empty blobs as rename source.
+
 ifndef::git-format-patch[]
 --check::
 	Warn if changes introduce conflict markers or whitespace errors.