Makefile: use completely separate spec-derived files for EXPERIMENTAL_FEATURES

This avoids overwriting the ones in git, and generally makes things neater.

We have convenience headers wire/peer_wire.h and wire/onion_wire.h to
avoid most #ifdefs: simply include those.

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

common/gossmap.c

@@ -20,7 +20,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
-#include <wire/peer_wiregen.h>
+#include <wire/peer_wire.h>
 
 /* We need this global to decode indexes for hash functions */
 static struct gossmap *map;