Add eb-garamond font (close #2553)

@vcunat added license, changed attribute name according to the [rules],
and trivial refactoring.
[rules]: http://nixos.org/nixpkgs/manual/#idm140333184443184 ("package naming")

pkgs/data/fonts/eb-garamond/default.nix

@@ -0,0 +1,50 @@
+x@{builderDefsPackage
+  , unzip
+  , ...}:
+builderDefsPackage
+(a :
+let
+  helperArgNames = ["stdenv" "fetchurl" "builderDefsPackage"] ++
+    [];
+
+  buildInputs = map (n: builtins.getAttr n x)
+    (builtins.attrNames (builtins.removeAttrs x helperArgNames));
+  sourceInfo = rec {
+    version="0.016";
+    name="EBGaramond";
+    url="https://bitbucket.org/georgd/eb-garamond/downloads/${name}-${version}.zip";
+    hash="0y630khn5zh70al3mm84fs767ac94ffyz1w70zzhrhambx07pdx0";
+  };
+in
+rec {
+  src = a.fetchurl {
+    url = sourceInfo.url;
+    sha256 = sourceInfo.hash;
+  };
+
+  name = "eb-garamond-${sourceInfo.version}";
+  inherit buildInputs;
+
+  phaseNames = ["doUnpack" "installFonts"];
+
+  # This will clean up if/when 8263996 lands.
+  doUnpack = a.fullDepEntry (''
+    unzip ${src}
+    cd ${sourceInfo.name}*
+    mv {ttf,otf}/* .
+  '') ["addInputs"];
+
+  meta = with a.lib; {
+    description = "Digitization of the Garamond shown on the Egenolff-Berner specimen";
+    maintainers = with maintainers; [ relrod ];
+    platforms = platforms.all;
+    license = licenses.ofl;
+    homepage = http://www.georgduffner.at/ebgaramond/;
+  };
+  passthru = {
+    updateInfo = {
+      downloadPage = "https://github.com/georgd/EB-Garamond/releases";
+    };
+  };
+}) x
+

pkgs/top-level/all-packages.nix

@@ -7638,6 +7638,8 @@ let
 
   dosemu_fonts = callPackage ../data/fonts/dosemu-fonts { };
 
+  eb-garamond = callPackage ../data/fonts/eb-garamond { };
+
   freefont_ttf = callPackage ../data/fonts/freefont-ttf { };
 
   freepats = callPackage ../data/misc/freepats { };