* A command to register successor fstate expressions.

Unifying substitutes and successors isn't very feasible for now,
  since substitutes are only used when no path with a certain is
  known.  Therefore, a normal form of some expression stored as a
  substitute would not be used unless the expression itself was
  missing.

src/fstate.hh

@@ -93,5 +93,8 @@ ATerm termFromHash(const Hash & hash, string * p = 0);
 /* Write an aterm to the Nix store directory, and return its hash. */
 Hash writeTerm(ATerm t, const string & suffix, string * p = 0);
 
+/* Register a successor. */
+void registerSuccessor(const Hash & fsHash, const Hash & scHash);
+
 
 #endif /* !__EVAL_H */