Can't serve a directory and watching a sub-directory

I have the following directory structure:

$ tree .
.
├── build
│   └── foo.js
└── index.html

$ cat index.html
<html>
  <head>
    <title>foo</title>
  </head>
  <body>
  </body>
  <script>
    console.log(new Date().toTimeString());
  </script>
</html>

I would like devd to (1) serve files from the top-directory (basically index.html) and (2) reload when build/foo.js (or any other file in build/ changes). In particular, I don't want devd to reload if index.html (or any other file outside of build/) is changed.

I have tried several alternatives with no success:

devd -w build/ -l .: reloads when index.html is changed (and I don't want that)
devd -w build/ -L .: never reloads, even if build/foo.js is changed

cortesi / devd

Can't serve a directory and watching a sub-directory #116