A context for warnings.
Contexts are usually vl-context1s. However, for more
generality, you can use any arbitrary object as a context. The proper way to
do this is to wrap it using
Macro:
(defmacro vl-context (x) (cons 'vl-context-fix (cons x 'nil)))
Macro:
(defmacro make-vl-context (&rest args) (cons 'vl-context (cons (cons 'make-vl-context1 args) 'nil)))