script: make DER for signature encoding optional.

Alpha does the sane thing, places signatures raw.

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

Makefile

@@ -5,6 +5,8 @@ PROTOCC:=protoc-c
 
 # Alpha has checksequenceverify, segregated witness+input-amount-in-sig+confidentual-transactions, schnorr
 #FEATURES := -DHAS_CSV=1 -DALPHA_TXSTYLE=1 -DUSE_SCHNORR=1
+# Bitcoin uses DER for signatures
+FEATURES := -DSCRIPTS_USE_DER
 
 PROGRAMS := test-cli/open-channel test-cli/open-anchor-scriptsigs test-cli/leak-anchor-sigs test-cli/open-commit-sig test-cli/check-commit-sig test-cli/check-anchor-scriptsigs test-cli/get-anchor-depth test-cli/create-steal-tx test-cli/create-commit-spend-tx test-cli/close-channel test-cli/create-close-tx test-cli/update-channel test-cli/update-channel-accept test-cli/update-channel-signature test-cli/update-channel-complete test-cli/create-commit-tx
 

bitcoin/script.c

@@ -85,15 +85,22 @@ static void add_push_key(u8 **scriptp, const struct pubkey *key)
 	add_push_bytes(scriptp, key->key, pubkey_len(key));
 }
 
-/* Bitcoin wants DER encoding. */
 static void add_push_sig(u8 **scriptp, const struct bitcoin_signature *sig)
 {
+/* Bitcoin wants DER encoding. */
+#ifdef SCRIPTS_USE_DER
 	u8 der[73];
 	size_t len = signature_to_der(der, &sig->sig);
 
 	/* Append sighash type */
 	der[len++] = sig->stype;
 	add_push_bytes(scriptp, der, len);
+#else /* Alpha uses raw encoding */
+	u8 with_sighash[sizeof(sig->sig) + 1];
+	memcpy(with_sighash, &sig->sig, sizeof(sig->sig));
+	with_sighash[sizeof(sig->sig)] = sig->stype;
+	add_push_bytes(scriptp, with_sighash, sizeof(with_sighash));
+#endif
 }
 
 /* FIXME: permute? */