warning that base point might change for release version, to better integrate with x25510/448 or ed

src/gen_headers/decaf_h.py

@@ -73,7 +73,14 @@ extern const %(c_ns)s_scalar_t %(c_ns)s_scalar_zero API_VIS;
 /** The identity point on the curve. */
 extern const %(c_ns)s_point_t %(c_ns)s_point_identity API_VIS;
 
-/** An arbitrarily chosen base point on the curve. */
+/** An arbitrarily chosen base point on the curve.
+ * @warning TODO: this is subject to change.  It is currently
+ * the preimage of the X%(gf_shortname)s base point.  Sometime
+ * soon, we will merge and finalize support for X%(gf_shortname)s
+ * and Ed%(gf_shortname)s integration.  This might make some
+ * multiple of the current basepoint (eg twice it, or the cofactor
+ * times it) more convenient API-wise, and trigger a changeover.
+ */
 extern const %(c_ns)s_point_t %(c_ns)s_point_base API_VIS;
 
 /** Precomputed table for the base point on the curve. */