Dockerfile fails to build

[madwort]

Was just attempting to build this using /examples/docker/Dockerfile, with the oldest easily working image archlinux:20200908 I get this failure - seems like emscripten has removed some stuff from the allocate function so some stuff will need updating...

...
make[1]: Leaving directory '/piper-vamp-js/examples/vamp-test-plugin'
make -C examples/vamp-example-plugins test-wasm
make[1]: Entering directory '/piper-vamp-js/examples/vamp-example-plugins'
node /piper-vamp-js/test/node-load-test.js /piper-vamp-js/examples/vamp-example-plugins/VampExamplePlugins_w.umd.js
Loading library "/piper-vamp-js/examples/vamp-example-plugins/VampExamplePlugins_w.umd.js"...
Listing plugins...
Assertion failed: allocate no longer takes a type argument
RuntimeError: abort(Assertion failed: allocate no longer takes a type argument) at Error
    at jsStackTrace (/piper-vamp-js/examples/vamp-example-plugins/VampExamplePlugins_w.umd.js:10:366954)
    at stackTrace (/piper-vamp-js/examples/vamp-example-plugins/VampExamplePlugins_w.umd.js:10:367130)
    at abort (/piper-vamp-js/examples/vamp-example-plugins/VampExamplePlugins_w.umd.js:10:30516)
    at assert (/piper-vamp-js/examples/vamp-example-plugins/VampExamplePlugins_w.umd.js:10:20512)
    at Object.allocate (/piper-vamp-js/examples/vamp-example-plugins/VampExamplePlugins_w.umd.js:10:21730)
    at request (/piper-vamp-js/test/node-load-test.js:99:24)
    at test (/piper-vamp-js/test/node-load-test.js:165:24)
    at /piper-vamp-js/test/node-load-test.js:260:5
/piper-vamp-js/examples/vamp-example-plugins/VampExamplePlugins_w.umd.js:10
...