diff-parseopt: convert --no-renames|--[no--rename-empty

For --rename-empty, see 90d43b07 (teach diffcore-rename to
optionally ignore empty content - 2012-03-22) for more information.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/diff-options.txt

@@ -392,6 +392,9 @@ 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.

diff.c

@@ -5087,6 +5087,11 @@ static void prep_parse_options(struct diff_options *options)
 			       diff_opt_find_copies),
 		OPT_BOOL(0, "find-copies-harder", &options->flags.find_copies_harder,
 			 N_("use unmodified files as source to find copies")),
+		OPT_SET_INT_F(0, "no-renames", &options->detect_rename,
+			      N_("disable rename detection"),
+			      0, PARSE_OPT_NONEG),
+		OPT_BOOL(0, "rename-empty", &options->flags.rename_empty,
+			 N_("use empty blobs as rename source")),
 
 		OPT_GROUP(N_("Diff other options")),
 		{ OPTION_CALLBACK, 0, "output", options, N_("<file>"),
@@ -5121,13 +5126,7 @@ int diff_opt_parse(struct diff_options *options,
 		return ac;
 
 	/* renames options */
-	if (!strcmp(arg, "--no-renames"))
-		options->detect_rename = 0;
-	else if (!strcmp(arg, "--rename-empty"))
-		options->flags.rename_empty = 1;
-	else if (!strcmp(arg, "--no-rename-empty"))
-		options->flags.rename_empty = 0;
-	else if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
+	if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
 		options->flags.relative_name = 1;
 		if (arg)
 			options->prefix = arg;