* 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

tests/lang/eval-okay-search-path.exp

@@ -1 +1 @@
-"abc"
+"abcc"

tests/lang/eval-okay-search-path.flags

@@ -1 +1 @@
--I lang/dir1 -I lang/dir2
+-I lang/dir1 -I lang/dir2 -I dir5=lang/dir3

tests/lang/eval-okay-search-path.nix

@@ -1,3 +1,3 @@
-import <a.nix> + import <b.nix> + import <c.nix>
+import <a.nix> + import <b.nix> + import <c.nix> + import <dir5/c.nix>