Undo (soft) breaking change introduced in 93c0a35 & #816.

[indexzero]

We say "soft" breaking because it was not a strict contract between react-intl and
consumers that raw src/* files be included in the npm package. If one were to want
a custom build of react-intl for their own purposes the npm package is now no longer
a viable location for that source code.

[yahoocla]

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[Swaagie]

@indexzero https://github.com/yahoo/react-intl/blob/master/package.json#L34 is exposed as ES6 from the npm package though. So the issue might be as simple as getting the builder to pickup on that over main

[indexzero]

There is more complexity here. The logic behind a custom build generally centers around avoiding additional calls to addLocaleData. Even though there is an ES6 main now, that is a rollup based build, so there is no way to ignore src/en.js if you do not wish to include the default locale data.

Overall for the react-intl maintainers who will eventually read this: removing the source files from an npm package is a breaking change because the implicit contract you were making before was "hey, here's the raw individual source files if you want to use them directly". That contract was broken in #816. Overall those src files are only an additional 12k in your npm package:

tar -czvf src.tgz src/
ls -al src.tgz
-rw-r--r--  1 [redacted]  11673 Apr 21 13:35 src.tgz

... so while I can appreciate the desire for a smaller build this change has very little impact on anyone w.r.t. number of bytes downloaded.

[okuryu]

Okay, let's merge this.