--- /dev/null
+/* header file for the curve25519-donna implementation, because the
+ * authors of that project don't supply one.
+ */
+#ifndef CURVE25519_DONNA_H
+#define CURVE25519_DONNA_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern int curve25519_donna(unsigned char *output, const unsigned char *a,
+ const unsigned char *b);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif