allowing --master-data without arg to be compatible with < 4.1.8 mysqldump.

client/mysqldump.c

@@ -254,7 +254,7 @@ static struct my_option my_long_options[] =
    "any action on logs will happen at the exact moment of the dump."
    "Option automatically turns --lock-tables off.",
    (gptr*) &opt_master_data, (gptr*) &opt_master_data, 0,
-   GET_UINT, REQUIRED_ARG, 0, 0, MYSQL_OPT_MASTER_DATA_COMMENTED_SQL, 0, 0, 0},
+   GET_UINT, OPT_ARG, 0, 0, MYSQL_OPT_MASTER_DATA_COMMENTED_SQL, 0, 0, 0},
   {"max_allowed_packet", OPT_MAX_ALLOWED_PACKET, "",
     (gptr*) &opt_max_allowed_packet, (gptr*) &opt_max_allowed_packet, 0,
     GET_ULONG, REQUIRED_ARG, 24*1024*1024, 4096, 
@@ -548,6 +548,10 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
   case '?':
     usage();
     exit(0);
+  case (int) OPT_MASTER_DATA:
+    if (!argument) /* work like in old versions */
+      opt_master_data= MYSQL_OPT_MASTER_DATA_EFFECTIVE_SQL;
+    break;
   case (int) OPT_OPTIMIZE:
     extended_insert= opt_drop= opt_lock= quick= create_options=
       opt_disable_keys= lock_tables= opt_set_charset= 1;