additional fixes for org-mode 9.1.

ox-twiki.el

@@ -317,7 +317,7 @@ contextual information."
      (org-twiki-fix-targets contents)
      ;; Footnotes
      (let ((definitions (org-export-collect-footnote-definitions
-			 (plist-get info :parse-tree) info))
+			 info (plist-get info :parse-tree)))
 	   ;; Insert full links right inside the footnote definition
 	   ;; as they have no chance to be inserted later.
 	   (org-ascii-links-to-notes nil))

rules.org

@@ -5,6 +5,8 @@
 #+EMAIL: Correspondence to snyder@bnl.gov.
 # Checked with org-mode 9.1.9 (as bundled with emacs 26.2)
 # To export to PDF use `org-latex-export-to-pdf'.
+# To export to HTML use `org-html-export-to-html'.
+# To export to TWiki, load ox-twiki.el and use `org-twiki-export-as-twiki.
 
 # Along with the change to org-export-dictionary below, this changes
 # the `Footnotes' section in HTML to `References'
@@ -3165,7 +3167,7 @@ Doxygen also knows about //!< , I think?
 # eval: (nconc (assoc "Footnotes" org-export-dictionary) '(("en-references" :default "References")))
 # eval: (defun my-target-filter (text backend info) (when (org-export-derived-backend-p backend 'latex) (replace-regexp-in-string "\\label" "\mylabel" text t t)))
 # eval: (add-to-list 'org-export-filter-target-functions 'my-target-filter)
-# eval: (defun org-html-target (target contents info) (let ((id (org-export-solidify-link-text (org-element-property :value target)))) (org-html--anchor id id)))
+# eval: (defun org-html-target (target _contents info)  (let ((ref (org-export-get-reference target info)) (text (org-element-property :value target))) (org-html--anchor text text nil info)))
 # eval: (setq org-export-with-email t)
 # eval: (setq org-latex-prefer-user-labels t)
 # eval: (define-advice org-latex--text-markup (:filter-return (text) brocket-fix) (if (string= (substring text 0 8) "\\texttt{") (replace-regexp-in-string "<<" "<{}<" (replace-regexp-in-string ">>" ">{}>" text))     text))  ; fix bad formatting of << and >>