Cross platform bit twiddling without the price

All our bit twiddling ops are written with great care to work both in native and JS. However it means that native platforms are using suboptimal expressions.

Solution 1:

Use conditional readers and have :cljd/js for branches specific to JS.
Pro: easy enough, integrates well with the clojure model
Cons: have to pass specific flag when compiling to web (and flutter sometimes default to web without us knowing)

Solution 2:

Have a special form and emit each branch of this form in a distinct lib (js or not). Use dart conditional imports to load the right one.
However most defns concerned by this issue have inlines and thus call sites would expand differently.

Solution 2.1:

Get rid of clojure inlines for these defns and use the "vm:prefer-inline" pragma (see https://github.com/dart-lang/sdk/issues/51977) to ask the Dart compiler to perform the inline

Solution 2.2:

Emit all nses as two libs (one js, one not). Details have to be figured out to see if an extra pass is required.

No source files or tests are named. Start by comparing the proposed conditional readers, :cljd/js branches, Dart conditional imports, and vm:prefer-inline approach, then determine how inline call sites and Flutter web compilation are affected. Done means native platforms use platform-appropriate bit operations without sacrificing JavaScript behavior.