Achieving portability, how?

[Christopher Fry <cfry@OZ.AI.MIT.EDU>]

    There seem to be several ways to achieve portability:
    ...
  
    (3) Provide tools for examining the text (source) of a program and reporting
    any non-portable syntax. These tools could be used anywhere.

Agreed, no matter what else is decided.
Nice candidate for the yellow pages. It could check each function call to
a valid CL fn that you were passing a correct number of args to it as well.

That would go a long way to catching those calls to CL fns 
where an implementation added that addition &optional arg which is
illegal.