mysqld.cc:

  innodb_fast_shutdown CAN take an argument though it was not specified so in mysqld.cc

sql/mysqld.cc

@@ -3346,7 +3346,7 @@ struct my_option my_long_options[] =
    0, 0, 0},
   {"innodb_fast_shutdown", OPT_INNODB_FAST_SHUTDOWN,
    "Speeds up server shutdown process", (gptr*) &innobase_fast_shutdown,
-   (gptr*) &innobase_fast_shutdown, 0, GET_BOOL, NO_ARG, 1, 0, 0, 0, 0, 0},
+   (gptr*) &innobase_fast_shutdown, 0, GET_BOOL, OPT_ARG, 1, 0, 0, 0, 0, 0},
   {"innodb_max_dirty_pages_pct", OPT_INNODB_MAX_DIRTY_PAGES_PCT,
    "Percentage of dirty pages allowed in bufferpool", (gptr*) &srv_max_buf_pool_modified_pct,
    (gptr*) &srv_max_buf_pool_modified_pct, 0, GET_ULONG, REQUIRED_ARG, 90, 0, 100, 0, 0, 0},