Caveats:
- keyword function definitions do not define static
bindings, thus limiting optimization opportunities
- can't use `define:`, `lambda:`, etc with keywords
- error messages sometimes expose the implementation
- the optimizer skips most of the generated code for
keyword functions definitions (user-level code is
optimized)
Macros and other tools that need syntax privilege used
`(current-code-inspector)' at the module top-level to try to
capture the right code inspector at load time. It's more
consistent to instead use the enclosing module's declaration-time
inspector, and `var-ref->mod-decl-insp' provides that. The
new function works only on references to anonymous variables,
which limits access to the inspector.
The real function name is longer, of course.
