LAMBDA: Properly create new context in accordance with the new environment.
LAMBDA: Do not reserve environment space for special variables.
Simplify.
Simplify.
LAMBDA: Simplify.
Reindent.
LAMBDA: Fix argument processing counter.
Use SBCL primitives instead of PROGV (experimental!).
Simplify.
LAMBDA: Simplify, (DECLARE (DYNAMIC-EXTENT ARGS)).