0.9.12.20:

0.9.12.20:
	Get rid of the PCL method-lambda macrolets completely (see also
        0.9.12.6).

        * Replace PV-ENV with a global macro that switches its behaviour
          based on the environment where it's expanded.
        * The macrolets created by BIND-*-LEXICAL-METHOD-MACROS
          were only used by BIND-LEXICAL-METHOD-FUNCTIONS. Merge them into a
          BIND-*-LEXICAL-METHOD-FUNCTIONS without the macrolets. Also remove
          some dead code in the macros (I'm sure it made sense 15 years ago).