Let user to choose python2.4 or python2.5

Currently, there is some code duplication. I'll try to rewrite it without
modifying resulting derivations.

svn path=/nixpkgs/trunk/; revision=9670

pkgs/development/interpreters/python/default.nix

@@ -1,52 +1,5 @@
-{stdenv, fetchurl, zlib ? null, zlibSupport ? true, bzip2}:
-
-assert zlibSupport -> zlib != null;
-
-with stdenv.lib;
-
-let
-
-  buildInputs =
-    optional (stdenv ? gcc && stdenv.gcc.libc != null) stdenv.gcc.libc ++
-    [bzip2] ++ 
-    optional zlibSupport zlib;
-
-in
-
-stdenv.mkDerivation {
-  name = "python-2.4.4";
-  
-  src = fetchurl {
-    url = http://www.python.org/ftp/python/2.4.4/Python-2.4.4.tar.bz2;
-    md5 = "0ba90c79175c017101100ebf5978e906";
-  };
-
-  patches = [
-    # Look in C_INCLUDE_PATH and LIBRARY_PATH for stuff.
-    ./search-path.patch
-  ];
-  
-  inherit buildInputs;
-  C_INCLUDE_PATH = concatStringsSep ":" (map (p: "${p}/include") buildInputs);
-  LIBRARY_PATH = concatStringsSep ":" (map (p: "${p}/lib") buildInputs);
-  
-  configureFlags = "--enable-shared";
-  
-  preConfigure = "
-    # Purity.
-    for i in /usr /sw /opt /pkg; do 
-      substituteInPlace ./setup.py --replace $i /no-such-path
-    done
-  ";
-  
-  postInstall = "
-    ensureDir $out/nix-support
-    cp ${./setup-hook.sh} $out/nix-support/setup-hook
-    rm -rf $out/lib/python2.4/test
-  ";
-
-  passthru = {
-    inherit zlibSupport;
-    libPrefix = "python2.4";
-  };
+args: rec {
+	default = v_2_4;
+	v_2_4 = import ./2.4.nix args;
+	v_2_5 = import ./2.5 args;
 }