Can't build after `git clone`

After fresh `git clone` and `npm install` or manual `npm run build` I get this error:
```
$ npm run build

> preact-virtual-list@0.3.1 build /home/gabriel/opt/preact-virtual-list
> npm-run-all transpile optimize minify

> preact-virtual-list@0.3.1 transpile /home/gabriel/opt/preact-virtual-list
> rollup -c rollup.config.js -m ${npm_package_main}.map -f umd -n $npm_package_amdName $npm_package_jsnext_main -o $npm_package_main

resolve failed for "babel-runtime": Error: Cannot find module 'babel-runtime'
Treating 'preact' as external dependency
No name was provided for external module 'preact' in options.globals – guessing 'preact'
Bad sourcemap
Error: Bad sourcemap
at Object.traceSegment (/home/gabriel/opt/preact-virtual-list/node_modules/rollup/www/ROLLUP/rollup/src/utils/collapseSourcemaps.js:75:26)
at /home/gabriel/opt/preact-virtual-list/node_modules/rollup/www/ROLLUP/rollup/src/utils/collapseSourcemaps.js:31:27
at Array.forEach (native)
at /home/gabriel/opt/preact-virtual-list/node_modules/rollup/www/ROLLUP/rollup/src/utils/collapseSourcemaps.js:29:9
at Array.map (native)
at Object.traceMappings (/home/gabriel/opt/preact-virtual-list/node_modules/rollup/www/ROLLUP/rollup/src/utils/collapseSourcemaps.js:26:34)
at collapseSourcemaps (/home/gabriel/opt/preact-virtual-list/node_modules/rollup/www/ROLLUP/rollup/src/utils/collapseSourcemaps.js:102:37)
at Bundle.render (/home/gabriel/opt/preact-virtual-list/node_modules/rollup/www/ROLLUP/rollup/src/Bundle.js:280:11)
at Object.write (/home/gabriel/opt/preact-virtual-list/node_modules/rollup/www/ROLLUP/rollup/src/rollup.js:62:32)
at /home/gabriel/opt/preact-virtual-list/node_modules/rollup/bin/runRollup.js:138:18
Type rollup --help for help, or visit https://github.com/rollup/rollup/wiki
```

Inizia dagli script di package.json e rollup.config.js, quindi riproduci il problema con npm install e npm run build. Verifica perché babel-runtime non è disponibile e accertati che un clone pulito possa completare la build senza errori di modulo mancante o di sourcemap non valido.

Scritto dal modello di indicizzazione a partire dal testo della issue.