* Allow redirections in search path entries. E.g. if you have a

directory

    /home/eelco/src/stdenv-updates

  that you want to use as the directory for import such as

    with (import <nixpkgs> { });

  then you can say

    $ nix-build -I nixpkgs=/home/eelco/src/stdenv-updates

src/libexpr/eval.hh

@@ -213,8 +213,9 @@ private:
 
     std::map<Path, Expr *> parseTrees;
 
-    Paths searchPath;
-    Paths::iterator searchPathInsertionPoint;
+    typedef list<std::pair<string, Path> > SearchPath;
+    SearchPath searchPath;
+    SearchPath::iterator searchPathInsertionPoint;
 
 public: