0.9.15.26: compiler-macro lambda-list parsing and FUNCALL forms

0.9.15.26: compiler-macro lambda-list parsing and FUNCALL forms
 * We previously handled only the &WHOLE case, and also failed to
   handle the argument count checking correct. Now things should work,
   but FUNCALL forms are not still subject to compiler-macroexpansion -- yet.
   (Reported by James Y Knight)
 * Refactor the macro-lambda-list parsing code slightly for easier
   comprehension.