cherry-pick, revert: add the --gpg-sign option

Signed-off-by: Nicolas Vigier <boklm@mars-attacks.org>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/sequencer.c b/sequencer.c
index 90cac7b..bde5f04 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -392,11 +392,18 @@
 {
 	struct argv_array array;
 	int rc;
+	char *gpg_sign;
 
 	argv_array_init(&array);
 	argv_array_push(&array, "commit");
 	argv_array_push(&array, "-n");
 
+	if (opts->gpg_sign) {
+		gpg_sign = xmalloc(3 + strlen(opts->gpg_sign));
+		sprintf(gpg_sign, "-S%s", opts->gpg_sign);
+		argv_array_push(&array, gpg_sign);
+		free(gpg_sign);
+	}
 	if (opts->signoff)
 		argv_array_push(&array, "-s");
 	if (!opts->edit) {
@@ -808,6 +815,8 @@
 		opts->mainline = git_config_int(key, value);
 	else if (!strcmp(key, "options.strategy"))
 		git_config_string(&opts->strategy, key, value);
+	else if (!strcmp(key, "options.gpg-sign"))
+		git_config_string(&opts->gpg_sign, key, value);
 	else if (!strcmp(key, "options.strategy-option")) {
 		ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 		opts->xopts[opts->xopts_nr++] = xstrdup(value);
@@ -981,6 +990,8 @@
 	}
 	if (opts->strategy)
 		git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
+	if (opts->gpg_sign)
+		git_config_set_in_file(opts_file, "options.gpg-sign", opts->gpg_sign);
 	if (opts->xopts) {
 		int i;
 		for (i = 0; i < opts->xopts_nr; i++)