Free/alloc every FIO_OPT_STR_STORE string

Makes ownership clear, though the freeing is a bit anal.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fio.h b/fio.h
index 8a79289..736fefb 100644
--- a/fio.h
+++ b/fio.h
@@ -691,6 +691,8 @@
 extern void fio_fill_default_options(struct thread_data *);
 extern int fio_show_option_help(const char *);
 extern void fio_options_dup_and_init(struct option *);
+extern void options_mem_dupe(struct thread_data *);
+extern void options_mem_free(struct thread_data *);
 #define FIO_GETOPT_JOB		0x89988998
 #define FIO_NR_OPTIONS		128