Add insert_dylib darwin package.

pkgs/os-specific/darwin/insert_dylib/default.nix

@@ -0,0 +1,18 @@
+{ stdenv, fetchFromGitHub, xcbuild }:
+
+stdenv.mkDerivation
+  { name = "insert_dylib-2016.08.28";
+    src = fetchFromGitHub
+      { owner = "Tyilo";
+        repo = "insert_dylib";
+        rev = "c8beef66a08688c2feeee2c9b6eaf1061c2e67a9";
+        sha256 = "0az38y06pvvy9jf2wnzdwp9mp98lj6nr0ldv0cs1df5p9x2qvbya";
+      };
+    buildInputs = [ xcbuild ];
+    installPhase =
+      ''
+        prog=$(find . -type f -name insert_dylib)
+        mkdir -p $out/bin
+        install -m755 $prog $out/bin
+      '';
+  }

pkgs/top-level/darwin-packages.nix

@@ -31,6 +31,8 @@ in
     inherit (darwin) opencflite;
   };
 
+  insert_dylib = callPackage ../os-specific/darwin/insert_dylib { };
+
   ios-cross = callPackage ../os-specific/darwin/ios-cross {
     inherit (darwin) binutils;
   };