Move build scripts into their own folder

build/builder.sh

@@ -0,0 +1,20 @@
+source $stdenv/setup
+
+# Copy files to a mutable directory.
+cp -r $src/* .
+
+# Hugo can't set baseUrl via CLI for multi-lingual hosts.
+# We have to manually edit the configuration.
+sed -i "$urlSub" config.toml
+
+# Build site with Hugo
+hugo $extraFlags
+
+# Output result
+mkdir $out
+cp -r public/$publicPath/* $out/
+
+# Render math in HTML and XML files.
+node $server &
+sleep 1
+find $out/ -regex "$out/.*\.html" | xargs ruby $converter