common: new directory for any shared objects.

To avoid everything pulling in HTLCs stuff to the opening daemon, we
split the channel and commit_tx routines into initial_channel and
initial_commit_tx (no HTLC support) and move full HTLC supporting versions
into channeld.

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

common/utils.c

@@ -0,0 +1,24 @@
+#include "utils.h"
+#include <ccan/str/hex/hex.h>
+
+secp256k1_context *secp256k1_ctx;
+
+char *tal_hexstr(const tal_t *ctx, const void *data, size_t len)
+{
+	char *str = tal_arr(ctx, char, hex_str_size(len));
+	hex_encode(data, len, str, hex_str_size(len));
+	return str;
+}
+
+char *tal_hex(const tal_t *ctx, const tal_t *data)
+{
+	return tal_hexstr(ctx, data, tal_len(data));
+}
+
+u8 *tal_hexdata(const tal_t *ctx, const void *str, size_t len)
+{
+	u8 *data = tal_arr(ctx, u8, hex_data_size(len));
+	if (!hex_decode(str, len, data, hex_data_size(len)))
+		return NULL;
+	return data;
+}