commit_tx: new file containing logic to create initial commitment transaction.

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

commit_tx.h

@@ -0,0 +1,15 @@
+#ifndef LIGHTNING_COMMIT_TX_H
+#define LIGHTNING_COMMIT_TX_H
+#include <ccan/tal/tal.h>
+#include "lightning.pb-c.h"
+
+struct sha256_double;
+
+/* Create commitment tx to spend the anchor tx output; doesn't fill in
+ * input scriptsig. */
+struct bitcoin_tx *create_commit_tx(const tal_t *ctx,
+				    OpenChannel *ours,
+				    OpenChannel *theirs,
+				    const struct sha256_double *anchor_txid,
+				    unsigned int anchor_output);
+#endif