This enables WASM_BIGINT while maintaining (hypothetical) Safari 14 support
by shimming BigInt64Array and BigUint64Array if they are missing. I think the
last time we tried to enable WASM_BIGINT was before #2019 so our chances
are significantly better this time.
This will fix dynamic linking bugs and yields a minor reduction in code size.
If no indexURL is provided, we throw and catch an error and
then use ErrorStackParser to calculate where pyodide.js has
been loaded from. Resolves#2290.
Question: But getting the URL from error stack trace is well... really
hacky. Can't we use
[`document.currentScript`](https://developer.mozilla.org/en-US/docs/Web/API/Document/currentScript)
or
[`import.meta.url`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import.meta)
instead?
Answer: `document.currentScript` works for the browser main thread.
`import.meta` works for es6 modules. In a classic webworker, I think there
is no approach that works. Also we would need some third approach for node
when loading a commonjs module using `require`. On the other hand, this
stack trace approach works for every case without any feature detection
code.
Antonio Cuni