This commit adds the `i18nUseExternalIds` option to the linker options,
as the compliance tests exercise compilation results with and without
this flag enabled. We therefore need to configure the linker to take
this option into account, as otherwise the compliance test output would
not be identical.
Additionally, this commit switches away from spread syntax to set
the default options. This introduced a problem when the user-provided
options object did specify the keys, but with an undefined value. This
would have prevented the default options from being applied.
PR Close#39707
This commit adds the basic building blocks for linking partial declarations.
In particular it provides a generic `FileLinker` class that delegates to
a set of (not yet implemented) `PartialLinker` classes.
The Babel plugin makes use of this `FileLinker` providing concrete classes
for `AstHost` and `AstFactory` that work with Babel AST. It can be created
with the following code:
```ts
const plugin = createEs2015LinkerPlugin({ /* options */ });
```
PR Close#39116
