Issue: ADJUST-ARRAY-NOT-ADJUSTABLE (Version 3)

[Jon L White <jonl@lucid.com>]

re: In both cases, the status quo
    allows careful programmers to write portable code as in:

	- Never adjust a "non-adjustable" array
	- Never use REQUIRE in a context that would cause file loading

    The, quite legitimate, objection to the status quo is that it makes it
    _very_ likely that programmers, being human and fallible, will
    accidently wind up producing non-portable code because the current
    versions of these features lack adaquate (read any) portable error
    checking. 

The problem with the Symbolics implementation (as conveyed to us by
those inside symbolics) is that there is *** no place available ***
in an array to remember the :adjustable option.  Hence it is not a
trivial option for them to accommodate to the "Lucid status quo".

However, the "compromise" proposal for REQUIRE would expose a global 
variable to make inhibition of vendor-specific extensions possible.
This would be trivial in anybody's implementation.


-- JonL --