don't let gzip depend on gzip

svn path=/nixpkgs/trunk/; revision=1576

pkgs/stdenv/nix-linux-static/gzip-static/builder.sh

@@ -1,5 +1,5 @@
 . $stdenv/setup
  
-tar zxvf $src
 mkdir $out
-cp -a gzip-1.3.3/* $out
+cp -a $src1 $out
+cp -a $src2 $out

pkgs/stdenv/nix-linux-static/gzip-static/default.nix

@@ -3,5 +3,6 @@
 stdenv.mkDerivation {
   name = "gzip-static-1.3.3";
   builder = ./builder.sh;
-  src = ./gzip-1.3.3-static.tar.gz;
+  src1 = ./gzip;
+  src2 = ./gunzip;
 }