Change network transmitted doubles to fio_fp64_t IEEE 754 type

Encode and decode when transferring over the network.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fio.h b/fio.h
index dce4d8d..1fb2118 100644
--- a/fio.h
+++ b/fio.h
@@ -197,7 +197,7 @@
 	unsigned long long trim_backlog;
 	unsigned int clat_percentiles;
 	unsigned int overwrite_plist;
-	double percentile_list[FIO_IO_U_LIST_MAX_LEN];
+	fio_fp64_t percentile_list[FIO_IO_U_LIST_MAX_LEN];
 
 	char *read_iolog_file;
 	char *write_iolog_file;
@@ -498,6 +498,7 @@
 extern int is_backend;
 extern int nr_clients;
 extern int log_syslog;
+extern const fio_fp64_t def_percentile_list[FIO_IO_U_LIST_MAX_LEN];
 
 extern struct thread_data *threads;