Problems compiling greenfield

Hi,
I have some problems compiling greenfield. Thank you in advance. Procedure:

cd /tmp
sudo apt-get install -y libffi-dev libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev webpack
npm install -g cmake-js
git clone https://github.com/udevbe/greenfield.git
cd greenfield/compositor/
npm install .

Error:

[67] ./web/src/style/greenfield.css 1.08 KiB {0} [built]
[73] ./web/src/index.js + 59 modules 490 KiB {0} [built]
     | ./web/src/index.js 3.77 KiB [built]
     | ./web/src/Session.js 4.05 KiB [built]
     | ./web/src/lib/libpixman-1.js 32.2 KiB [built]
     | ./web/src/Compositor.js 3.61 KiB [built]
     | ./web/src/lib/libxkbcommon.js 35.2 KiB [built]
     | ./web/src/Shell.js 3.51 KiB [built]
     | ./web/src/Seat.js 9.97 KiB [built]
     | ./web/src/DataDeviceManager.js 3.76 KiB [built]
     | ./web/src/Output.js 4.81 KiB [built]
     | ./web/src/Subcompositor.js 4.86 KiB [built]
     | ./web/src/XdgWmBase.js 8.22 KiB [built]
     | ./web/src/desktopshell/DesktopUserShell.js 2.56 KiB [built]
     | ./web/src/webshm/WebShm.js 3.55 KiB [built]
     | ./web/src/WebAppSocket.js 3.77 KiB [built]
     | ./web/src/WebAppLauncher.js 2.5 KiB [built]
     |     + 45 hidden modules
    + 59 hidden modules

WARNING in asset size limit: The following asset(s) exceed the recommended size limit (244 KiB).
This can impact web performance.
Assets: 
  libpixman-1.wasm (326 KiB)

WARNING in webpack performance recommendations: 
You can limit the size of your bundles by using import() or require.ensure to lazy load some parts of your application.
For more info visit https://webpack.js.org/guides/code-splitting/

ERROR in [copy-webpack-plugin] unable to locate '/tmp/greenfield/compositor/web/public/clients' at '/tmp/greenfield/compositor/web/public/clients'
Child html-webpack-plugin for "index.html":
     1 asset
    Entrypoint undefined = index.html
    [2] (webpack)/buildin/global.js 472 bytes {0} [built]
    [3] (webpack)/buildin/module.js 497 bytes {0} [built]
        + 2 hidden modules
npm ERR! code ELIFECYCLE
npm ERR! errno 2
npm ERR! greenfield-compositor@1.0.0 prepare: `npm run prepare:web:generate && webpack --config web/build.config/webpack.config.prod.js`
npm ERR! Exit status 2
npm ERR! 
npm ERR! Failed at the greenfield-compositor@1.0.0 prepare script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/ubuntu/.npm/_logs/2019-05-03T16_28_17_382Z-debug.log

udevbe / greenfield

Problems compiling greenfield #7