gfio: Add support for sending logs over the network

This is for things like bw log, latency logs, etc. We add
a new depedency, zlib, for this. The logs can be quite big and
the network is not necessarily super fast, so we compress them
using zlib.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/client.h b/client.h
index 5b9c277..3022816 100644
--- a/client.h
+++ b/client.h
@@ -59,10 +59,12 @@
 	void *client_data;
 };
 
+struct cmd_iolog_pdu;
 typedef void (client_cmd_op)(struct fio_client *, struct fio_net_cmd *);
 typedef void (client_eta_op)(struct jobs_eta *je);
 typedef void (client_timed_out_op)(struct fio_client *);
 typedef void (client_jobs_eta_op)(struct fio_client *client, struct jobs_eta *je);
+typedef void (client_iolog_op)(struct fio_client *client, struct cmd_iolog_pdu *);
 
 struct client_ops {
 	client_cmd_op		*text;
@@ -78,6 +80,7 @@
 	client_cmd_op		*stop;
 	client_cmd_op		*start;
 	client_cmd_op		*job_start;
+	client_iolog_op		*iolog;
 
 	unsigned int eta_msec;
 	int stay_connected;