anchor.diff:  
   ;; TODO: Report compilation errors.
   
  +(export-always 'nyxt-user-system)
   (defclass nyxt-user-system (asdf:system) ()
     (:documentation "Specialized systems for Nyxt users.
  -This automatically default :pathname to the `*config-file*' directory."))
  +This automatically defaults :pathname to the `*config-file*' directory.
  +See `define-nyxt-user-system' and `define-nyxt-user-system-and-load'."))
   
   (defvar *nyxt-user-systems-with-missing-dependencies* '())
   
  
positive.code:     (or path
          (nfiles:expand (make-instance 'config-directory-file)))))
  
  (defun load-system* (system &rest keys &key force force-not verbose version &allow-other-keys)
    "Like `asdf:load-system' but, instead of signaling an error on missing
  dependency, it warns the user, skips the load gracefully and returns NIL.
  
negative.code:      :components ,(mapcar #'ensure-component
                            components)))
  
  (export-always 'define-nyxt-user-system-and-load)
  (defmacro define-nyxt-user-system-and-load (name &rest args &key depends-on components
                                              &allow-other-keys)
    "Like `define-nyxt-user-system' but immediately call `load-system*' on the system.
  