Run exports through the same identifier generation as imports to ensure
that everything gets a unique identifier and then just make sure all the
appropriate wires are hooked up when dealing with exports and imports.
Closes#1496
Currently the import object constructed for the `--target web` output
only ever includes the current module as an one of the modules included.
With `wasm-bindgen`'s optimization to import directly from modules,
however, it's possible to have more modules imported from in the
generated wasm file. This commit ensures that the imports are hooked up
in the `--target web` es6 emulation mode, ensuring there aren't
extraneous errors about import objects.
This commit is an implementation of [RFC 6] which enables crates to
inline local JS snippets into the final output artifact of
`wasm-bindgen`. This is accompanied with a few minor breaking changes
which are intended to be relatively minor in practice:
* The `module` attribute disallows paths starting with `./` and `../`.
It requires paths starting with `/` to actually exist on the filesystem.
* The `--browser` flag no longer emits bundler-compatible code, but
rather emits an ES module that can be natively loaded into a browser.
Otherwise be sure to check out [the RFC][RFC 6] for more details, and
otherwise this should implement at least the MVP version of the RFC!
Notably at this time JS snippets with `--nodejs` or `--no-modules` are
not supported and will unconditionally generate an error.
[RFC 6]: https://github.com/rustwasm/rfcs/pull/6Closes#1311
