data/fonts: simpler cleanups

pkgs/data/fonts/lmodern/default.nix

@@ -1,23 +1,24 @@
-{ stdenv, fetchurl }:
+{ stdenv, fetchzip }:
 
-stdenv.mkDerivation {
+fetchzip {
   name = "lmodern-2.004.4";
-  
-  src = fetchurl {
-    url = mirror://debian/pool/main/l/lmodern/lmodern_2.004.4.orig.tar.gz;
-    sha256 = "1g1fmi9asw6x9arm5sy3r4jwz7zrrbcw6q4waj3iqs0iq525i1rw";
-  };
 
-  installPhase = ''
+  url = mirror://debian/pool/main/l/lmodern/lmodern_2.004.4.orig.tar.gz;
+
+  postFetch = ''
+    tar xzvf $downloadedFile
+
     mkdir -p $out/texmf-dist/
     mkdir -p $out/share/fonts/
 
-    cp -r ./* $out/texmf-dist/
-    cp -r fonts/{opentype,type1} $out/share/fonts/
+    cp -r lmodern-2.004.4/* $out/texmf-dist/
+    cp -r lmodern-2.004.4/fonts/{opentype,type1} $out/share/fonts/
 
-    ln -s $out/texmf* $out/share/
+    ln -s -r $out/texmf* $out/share/
   '';
 
+  sha256 = "13n7ls8ss4sffd6c1iw2wb5hbq642i0fmivm76mbqwf652l002i5";
+
   meta = {
     description = "Latin Modern font";
     platforms = stdenv.lib.platforms.unix;