developer: IFDEV() macro.

There are some more #if DEVELOPER one-liners coming, this makes them
clear, but still lets them stand out.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

common/utils.h

@@ -59,4 +59,15 @@ STRUCTEQ_DEF(ripemd160, 0, u);
  * complained on, so we can re-test as gcc evolves. */
 #define COMPILER_WANTS_INIT(compiler_versions) = 0
 
+/* For case where we want one thing if DEVELOPER, another if not, particularly
+ * for function parameters.
+ *
+ * Usefully, you can refer to DEVELOPER-only fields here. */
+#if DEVELOPER
+/* Make sure that nondev is evaluated, and valid */
+#define IFDEV(dev, nondev) ((void)(nondev), (dev))
+#else
+#define IFDEV(dev, nondev) (nondev)
+#endif
+
 #endif /* LIGHTNING_COMMON_UTILS_H */

lightningd/connect_control.c

@@ -339,11 +339,6 @@ int connectd_init(struct lightningd *ld)
 	int hsmfd;
 	struct wireaddr_internal *wireaddrs = ld->proposed_wireaddr;
 	enum addr_listen_announce *listen_announce = ld->proposed_listen_announce;
-	bool allow_localhost = false;
-#if DEVELOPER
-	if (ld->dev_allow_localhost)
-		allow_localhost = true;
-#endif
 
 	if (socketpair(AF_LOCAL, SOCK_STREAM, 0, fds) != 0)
 		fatal("Could not socketpair for connectd<->gossipd");
@@ -370,7 +365,7 @@ int connectd_init(struct lightningd *ld)
 	    wireaddrs,
 	    listen_announce,
 	    ld->proxyaddr, ld->use_proxy_always || ld->pure_tor_setup,
-	    allow_localhost, ld->config.use_dns,
+	    IFDEV(ld->dev_allow_localhost, false), ld->config.use_dns,
 	    ld->tor_service_password ? ld->tor_service_password : "");
 
 	subd_req(ld->connectd, ld->connectd, take(msg), -1, 0,

lightningd/gossip_control.c

@@ -197,12 +197,7 @@ void gossip_init(struct lightningd *ld, int connectd_fd)
 	    ld->rgb,
 	    ld->alias, ld->config.channel_update_interval,
 	    ld->announcable,
-#if DEVELOPER
-	    ld->dev_gossip_time ? &ld->dev_gossip_time: NULL
-#else
-	    NULL
-#endif
-		);
+	    IFDEV(ld->dev_gossip_time ? &ld->dev_gossip_time: NULL, NULL));
 	subd_send_msg(ld->gossip, msg);
 }
 

lightningd/hsm_control.c

@@ -98,15 +98,10 @@ void hsm_init(struct lightningd *ld)
 	if (!wire_sync_write(ld->hsm_fd, towire_hsm_init(tmpctx,
 							 &ld->topology->bitcoind->chainparams->bip32_key_version,
 							 &chainhash,
-#if DEVELOPER
-							 ld->dev_force_privkey,
-							 ld->dev_force_bip32_seed,
-							 ld->dev_force_channel_secrets,
-							 ld->dev_force_channel_secrets_shaseed
-#else
-							 NULL, NULL, NULL, NULL
-#endif
-				     )))
+							 IFDEV(ld->dev_force_privkey, NULL),
+							 IFDEV(ld->dev_force_bip32_seed, NULL),
+							 IFDEV(ld->dev_force_channel_secrets, NULL),
+							 IFDEV(ld->dev_force_channel_secrets_shaseed, NULL))))
 		err(1, "Writing init msg to hsm");
 
 	ld->wallet->bip32_base = tal(ld->wallet, struct ext_key);

lightningd/subd.c

@@ -508,11 +508,9 @@ out:
 static void destroy_subd(struct subd *sd)
 {
 	int status;
-	bool fail_if_subd_fails = false;
+	bool fail_if_subd_fails;
 
-#if DEVELOPER
-	fail_if_subd_fails = sd->ld->dev_subdaemon_fail;
-#endif
+	fail_if_subd_fails = IFDEV(sd->ld->dev_subdaemon_fail, false);
 
 	switch (waitpid(sd->pid, &status, WNOHANG)) {
 	case 0: