define what `export` does

[flying-sheep]

ideas would be

• nothing

or another idea that i’m going to explore:

• treat export foo as window.foo = ...
• allow <module target="varname"/> to specify a global name for export default foo to bind to.

those 2 are independent but share the same idea that exports interact with window in browser contexts.

when going that route we could also think about explicitly importing browser-specific APIs: import window, {name} from 'browser-window'