nerdfonts: disable Windows font variants

The only difference between these and the regular fonts is that
the internal font name is limited to 31 characters. They double
the package closure size.

pkgs/data/fonts/nerdfonts/default.nix

@@ -5,6 +5,9 @@
 # To select only certain fonts, put a list of strings to `fonts`: every key in
 # ./shas.nix is an optional font
 , fonts ? []
+# Whether to enable Windows font variants, their internal font name is limited
+# to 31 characters
+, enableWindowsFonts ? false
 }:
 
 let
@@ -50,6 +53,10 @@ stdenv.mkDerivation rec {
   installPhase = ''
     find -name \*.otf -exec mkdir -p $out/share/fonts/opentype/NerdFonts \; -exec mv {} $out/share/fonts/opentype/NerdFonts \;
     find -name \*.ttf -exec mkdir -p $out/share/fonts/truetype/NerdFonts \; -exec mv {} $out/share/fonts/truetype/NerdFonts \;
+    ${lib.optionalString (! enableWindowsFonts) ''
+      rm -rfv $out/share/fonts/opentype/NerdFonts/*Windows\ Compatible.*
+      rm -rfv $out/share/fonts/truetype/NerdFonts/*Windows\ Compatible.*
+    ''}
   '';
 
   meta = with stdenv.lib; {