vistafonts: make the font derivation fixed-output

- [x] make the font derivation fixed-output (https://github.com/NixOS/nixpkgs/issues/27754)

pkgs/data/fonts/vista-fonts/default.nix

@@ -1,24 +1,14 @@
-{stdenv, fetchurl, cabextract}:
+{stdenv, fetchzip, cabextract}:
 
-stdenv.mkDerivation {
+fetchzip {
   name = "vista-fonts-1";
 
-  src = fetchurl {
+  url = http://download.microsoft.com/download/f/5/a/f5a3df76-d856-4a61-a6bd-722f52a5be26/PowerPointViewer.exe;
-    url = http://download.microsoft.com/download/f/5/a/f5a3df76-d856-4a61-a6bd-722f52a5be26/PowerPointViewer.exe;
-    sha256 = "07vhjdw8iip7gxk6wvp4myhvbn9619g10j9qvpbzz4ihima57ry4";
-  };
 
-  buildInputs = [cabextract];
+  postFetch = ''
+    ${cabextract}/bin/cabextract --lowercase --filter ppviewer.cab $downloadedFile
+    ${cabextract}/bin/cabextract --lowercase --filter '*.TTF' ppviewer.cab
 
-  unpackPhase = ''
-    cabextract --lowercase --filter ppviewer.cab $src
-    cabextract --lowercase --filter '*.TTF' ppviewer.cab
-    sourceRoot=.
-  '';
-
-  dontBuild = true;
-
-  installPhase = ''
     mkdir -p $out/share/fonts/truetype
     cp *.ttf $out/share/fonts/truetype
 
@@ -31,6 +21,8 @@ stdenv.mkDerivation {
     done
   '';
 
+  sha256 = "1q2d24c203vkl6pwk86frmaj6jra49hr9mydq7cnlx4hilqslw3g";
+
   meta = {
     description = "Some TrueType fonts from Microsoft Windows Vista (Calibri, Cambria, Candara, Consolas, Constantia, Corbel)";
     homepage = http://www.microsoft.com/typography/ClearTypeFonts.mspx;