184.108.40.206: physenvanal: When checking closure-DXness, handle XEPs reasonably.
* In ANALYZE-INDIRECT-LAMBDA-VARS, treat functionals as being DX if
either they are marked as being DX or they have a FUNCTIONAL-ENTRY-FUN
that is marked as being DX.
* This extends the existing logic to allow functions with XEPs (those
functions callable via the full-call convention) to use the