data/fonts: cleanup

* make font derivations fixed-output where applicable
 * fix dead links
 * `stdenv.lib` -> `lib` where `stdenv` is not involved
 * remove `meta.platforms = [ unix ]` and `meta.platforms = [ linux ]` because the restriction has no sense for data packages

pkgs/data/fonts/spleen/default.nix

@@ -1,23 +1,25 @@
-{ stdenv, fetchurl, mkfontdir, mkfontscale }:
+{ lib, fetchurl }:
 
-stdenv.mkDerivation rec {
+let
   pname = "spleen";
   version = "1.0.4";
+in fetchurl rec {
+  name = "${pname}-${version}";
+  url = "https://github.com/fcambus/spleen/releases/download/${version}/spleen-${version}.tar.gz";
 
-  src = fetchurl {
-    url = "https://github.com/fcambus/spleen/releases/download/${version}/spleen-${version}.tar.gz";
-    sha256 = "1x62a5ygn3rpgzbaacz64rp8mn7saymdnxci4l3xasvsjjp60s3g";
-  };
-
-  buildPhase = "gzip -n9 *.pcf";
-  installPhase = ''
+  downloadToTemp = true;
+  recursiveHash = true;
+  postFetch = ''
+    tar xf $downloadedFile --strip=1
     d="$out/share/fonts/X11/misc/spleen"
+    gzip -n9 *.pcf
     install -Dm644 *.pcf.gz  -t $d
     install -Dm644 *.bdf -t $d
     install -m644 fonts.alias-spleen $d/fonts.alias
   '';
+  sha256 = "0jab55h08gy7gpyxqfrfj30iinmknpllh3dp5g7ck5q3qfgdzh7m";
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     description = "Monospaced bitmap fonts";
     homepage = https://www.cambus.net/spleen-monospaced-bitmap-fonts;
     license = licenses.bsd2;