### What
This PR exposes new experimental configuration for next.js,
`experimental.reactCompiler`. Under the hood, this option configures to
use new experimental react compiler
(https://react.dev/learn/react-compiler#). `reactCompiler` value can be
either boolean or an object contains partial set of compiler itself's
configuration option.
For the webpack and turbopack both it is enabled by adding a babel
plugin for the react compiler. If user have an existing .babelrc, plugin
will be appended to the config. Otherwise, swc will still kicks in (for
webpack) or turbopack for the general transform but only compiler babel
plugin will run via babel.
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Co-authored-by: Tim Neutkens <tim@timneutkens.nl>
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