Makefile: fix distclean, clean targets.

libwally's tools/cleanup.sh doesn't actually remove files if it can't
run make, so do that manually.  Also clear some other cruft.

Also, we weren't deleting wire/gen_onion_wire.c in "make clean".

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

Makefile

@@ -356,8 +356,9 @@ update-secp256k1:
 distclean: clean
 	$(MAKE) -C secp256k1/ distclean || true
 	$(RM) libsecp256k1.a secp256k1/libsecp256k1.la
-	$(RM) libsodium.a libsodium/libsodium.la
+	$(RM) libsodium.a libsodium.la libsodium/libsodium.la
 	$(RM) libwallycore.a libwallycore.la
+	$(RM) libwally-core/src/secp256k1/libsecp256k1.la libwally-core/src/libwallycore.la
 	cd libwally-core && tools/cleanup.sh
 
 maintainer-clean: distclean

wire/Makefile

@@ -59,6 +59,6 @@ wire-maintainer-clean:
 wire-all: $(WIRE_OBJS) $(WIRE_ONION_OBJS)
 
 wire-clean:
-	$(RM) $(WIRE_OBJS) $(WIRE_ONION_OBJS) $(WIRE_GEN_SRC) $(WIRE_GEN_HEADERS)
+	$(RM) $(WIRE_OBJS) $(WIRE_ONION_OBJS) $(WIRE_GEN_SRC) $(WIRE_GEN_ONION_SRC) $(WIRE_GEN_HEADERS)
 
 include wire/test/Makefile