* Start of `nix-store --export' operation for serialising a store

path.  This is like `nix-store --dump', only it also dumps the
  meta-information of the store path (references, deriver).  Will add
  a `--sign' flag later to add a cryptographic signature, which we
  will use for exchanging store paths between build farm machines in a
  secure manner.

src/libstore/local-store.hh

@@ -56,6 +56,9 @@ public:
     Path addTextToStore(const string & suffix, const string & s,
         const PathSet & references);
 
+    void exportPath(const Path & path, bool sign,
+        Sink & sink);
+
     void buildDerivations(const PathSet & drvPaths);
 
     void ensurePath(const Path & path);