makeFontsCache: init

pkgs/development/libraries/fontconfig/make-fonts-cache.nix

···
+{ runCommand, lib, writeText, fontconfig, fontbhttf, fontDirectories }:
+
+runCommand "fc-cache"
+  rec {
+    buildInputs = [ fontconfig ];
+    passAsFile = [ "fontDirs" ];
+    fontDirs = ''
+      <!-- Font directories -->
+      ${lib.concatStringsSep "\n" (map (font: "<dir>${font}</dir>") fontDirectories)}
+    '';
+  }
+  ''
+    export FONTCONFIG_FILE=$(pwd)/fonts.conf
+
+    cat > fonts.conf << EOF
+    <?xml version='1.0'?>
+    <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
+    <fontconfig>
+      <include>${fontconfig}/etc/fonts/fonts.conf</include>
+      <cachedir>$out</cachedir>
+    EOF
+    cat "$fontDirsPath" >> fonts.conf
+    echo "</fontconfig>" >> fonts.conf
+
+    mkdir -p $out
+    fc-cache -sv
+  ''

pkgs/top-level/all-packages.nix

···
       inherit fontconfig fontDirectories;
     };
 
+  makeFontsCache = let fontconfig_ = fontconfig; in {fontconfig ? fontconfig_, fontDirectories}:
+    callPackage ../development/libraries/fontconfig/make-fonts-cache.nix {
+      inherit fontconfig fontDirectories;
+    };
+
   freealut = callPackage ../development/libraries/freealut { };
 
   freeglut = callPackage ../development/libraries/freeglut { };