vendor ibm-plex

i don't like how we're doing this lol. setting the IBM_PLEX_WEB env var feels wrong.

vendor/default.nix

@@ -0,0 +1,8 @@
+{ fetchzip
+, fetchurl
+, callPackage
+}:
+
+{
+  ibm-plex-web = callPackage ./ibm-plex-web.nix {};
+}

vendor/ibm-plex-web.nix

@@ -0,0 +1,21 @@
+# Differs from the Nixpkgs distribution in that we distribute WOFFs
+# and CSS rather than just OTF.
+{ ibm-plex
+, families ? []
+}@args:
+
+(ibm-plex.overrideAttrs (_prev: {
+  installPhase = ''
+    runHook preInstall
+    for i in $srcs; do
+      # cp $i/css/*.css $out/css
+      for j in css fonts/{complete,split}/{woff,woff2}; do
+        if [ -d $i/$j ]; then
+	  find $i/$j -type f -regex '.*\.\(woff2?\|css\)' \
+            -exec install -Dm644 -t $out/share/ibm-plex-web/$j {} \;
+        fi
+      done
+    done
+    runHook postInstall
+  '';
+})).override { inherit families; }