diff-parseopt: convert -S|-G

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -5056,6 +5056,28 @@ static int diff_opt_patience(const struct option *opt,
 	return 0;
 }
 
+static int diff_opt_pickaxe_regex(const struct option *opt,
+				  const char *arg, int unset)
+{
+	struct diff_options *options = opt->value;
+
+	BUG_ON_OPT_NEG(unset);
+	options->pickaxe = arg;
+	options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
+	return 0;
+}
+
+static int diff_opt_pickaxe_string(const struct option *opt,
+				   const char *arg, int unset)
+{
+	struct diff_options *options = opt->value;
+
+	BUG_ON_OPT_NEG(unset);
+	options->pickaxe = arg;
+	options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
+	return 0;
+}
+
 static int diff_opt_relative(const struct option *opt,
 			     const char *arg, int unset)
 {
@@ -5363,6 +5385,12 @@ static void prep_parse_options(struct diff_options *options)
 		OPT_SET_INT_F(0, "ita-visible-in-index", &options->ita_invisible_in_index,
 			      N_("treat 'git add -N' entries as real in the index"),
 			      0, PARSE_OPT_NONEG),
+		OPT_CALLBACK_F('S', NULL, options, N_("<string>"),
+			       N_("look for differences that change the number of occurrences of the specified string"),
+			       0, diff_opt_pickaxe_string),
+		OPT_CALLBACK_F('G', NULL, options, N_("<regex>"),
+			       N_("look for differences that change the number of occurrences of the specified regex"),
+			       0, diff_opt_pickaxe_regex),
 		{ OPTION_CALLBACK, 0, "output", options, N_("<file>"),
 		  N_("Output to a specific file"),
 		  PARSE_OPT_NONEG, NULL, 0, diff_opt_output },
@@ -5415,15 +5443,6 @@ int diff_opt_parse(struct diff_options *options,
 	}
 
 	/* misc options */
-	else if ((argcount = short_opt('S', av, &optarg))) {
-		options->pickaxe = optarg;
-		options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
-		return argcount;
-	} else if ((argcount = short_opt('G', av, &optarg))) {
-		options->pickaxe = optarg;
-		options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
-		return argcount;
-	}
 	else if (!strcmp(arg, "--pickaxe-all"))
 		options->pickaxe_opts |= DIFF_PICKAXE_ALL;
 	else if (!strcmp(arg, "--pickaxe-regex"))