gurobipy: Use buildPythonPackage on Darwin.

pkgs/development/python-modules/gurobipy/darwin.nix

@@ -1,26 +1,24 @@
-{ stdenv, fetchurl, python, xar, cpio, cctools, insert_dylib }:
+{ fetchurl, python, xar, cpio, cctools, insert_dylib }:
 assert python.pkgs.isPy27 && python.ucsEncoding == 2;
-stdenv.mkDerivation
+python.pkgs.buildPythonPackage
   { name = "gurobipy-7.0.2";
     src = fetchurl
       { url = "http://packages.gurobi.com/7.0/gurobi7.0.2_mac64.pkg";
         sha256 = "14dpxas6gx02kfb28i0fh68p1z4sbjmwg8hp8h5ch6c701h260mg";
       };
     buildInputs = [ xar cpio cctools insert_dylib ];
-    buildCommand =
+    unpackPhase =
       ''
-        # Unpack
         xar -xf $src
         zcat gurobi*mac64tar.pkg/Payload | cpio -i
         tar xf gurobi*_mac64.tar.gz
-
-        # Install
-        cd gurobi*/mac64
-        mkdir -p $out/lib/python2.7/site-packages
-        mv lib/python2.7/gurobipy $out/lib/python2.7/site-packages
-        mv lib/lib*.so $out/lib
-
-        # Fixup
+        sourceRoot=$(echo gurobi*/*64)
+        runHook postUnpack
+      '';
+    patches = [ ./no-darwin-fixup.patch ];
+    postInstall = "mv lib/lib*.so $out/lib";
+    postFixup =
+      ''
         install_name_tool -change \
           /System/Library/Frameworks/Python.framework/Versions/2.7/Python \
           ${python}/lib/libpython2.7.dylib \