Add --start-time option for backup

Author: dlepikhova

src/pg_probackup.c

@@ -78,6 +78,7 @@ pid_t       my_pid = 0;
 __thread int  my_thread_num = 1;
 bool		progress = false;
 bool		no_sync = false;
+time_t		start_time = 0;
 #if PG_VERSION_NUM >= 100000
 char	   *replication_slot = NULL;
 bool		temp_slot = false;
@@ -200,6 +201,7 @@ static ConfigOption cmd_options[] =
 	{ 's', 'i', "backup-id",		&backup_id_string,	SOURCE_CMD_STRICT },
 	{ 'b', 133, "no-sync",			&no_sync,			SOURCE_CMD_STRICT },
 	{ 'b', 134, "no-color",			&no_color,			SOURCE_CMD_STRICT },
+	{ 'U', 241, "start-time",		&start_time,		SOURCE_CMD_STRICT },
 	/* backup options */
 	{ 'b', 180, "backup-pg-log",	&backup_logs,		SOURCE_CMD_STRICT },
 	{ 'f', 'b', "backup-mode",		opt_backup_mode,	SOURCE_CMD_STRICT },
@@ -939,10 +941,9 @@ main(int argc, char *argv[])
 			return do_init(catalogState);
 		case BACKUP_CMD:
 			{
-				time_t start_time;
-				time(&start_time);
-
 				current.stream = stream_wal;
+				if (start_time == 0)
+					start_time = current_time;
 
 				/* sanity */
 				if (current.backup_mode == BACKUP_MODE_INVALID)