[eval2] Fix blocks in FLET, LABELS.
[eval2] Fix SETQ of symbol macros.
[eval2] Use a structure class for closures generated by eval2.
[eval2] Remove a debug-print.
[eval2] Sprinkle hooks for MINIMALLY-COMPILED-FUNCTIONs all over the code base.
[eval2] Simplify function calls.
[eval2] LAMBDA: Check keyword argument number.