>> Compiling file /usr/local/maxima-5.6/affine/amacros.lisp ...
>> ** - Continuable Error
>> Redefining the COMMON LISP function COPY-STRUCTURE
Doubtless you have a (defstruct structure) in your source, which
macroexpansion defines copy-structure, which clashes with the ANS
function of the same name.
If the copier is never used, you could specify (:copier nil) to the
defstruct to bypass definition of the copier function. On the other
hand, if the copier _is_ used, you can still specify (:copier nil)
because the predefined cl:copy-structure will do the same thing as the
copier being generated for this particular structure.