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.
original commit: 0197902309c5400d463393829a88282c627dafd2
