EXPERIMENTAL/org-e-latex: Use new footnote API

* EXPERIMENTAL/org-e-latex.el (org-e-latex-footnote-reference):
  Rewrite function to use new footnote API.

EXPERIMENTAL/org-e-latex.el

@@ -881,27 +881,24 @@ CONTENTS is nil. INFO is a plist holding contextual information."
      org-e-latex-footnote-separator)
    ;; Use \footnotemark if the footnote has already been defined.
    ;; Otherwise, define it with \footnote command.
-   (let* ((all-seen (plist-get info :seen-footnote-labels))
-	  (label (org-element-get-property :label footnote-reference))
-	  ;; Anonymous footnotes are always new footnotes.
-	  (seenp (and label (member label all-seen)))
-	  (inline-def-p (org-element-get-property
-			 :inline-definition footnote-reference)))
    (cond
-      (seenp (format "\\footnotemark[%s]" (length seenp)))
+    ((not (org-export-footnote-first-reference-p footnote-reference info))
+     (format "\\footnotemark[%s]"
+	     (org-export-get-footnote-number footnote-reference info)))
     ;; Inline definitions are secondary strings.
-      (inline-def-p
+    ((eq (org-element-get-property :type footnote-reference) 'inline)
      (format "\\footnote{%s}"
 	     (org-trim
-		(org-export-secondary-string inline-def-p 'latex info))))
+	      (org-export-secondary-string
-      ;; Non-inline footnotes necessarily contain a label.  Retrieve
+	       (org-export-get-footnote-definition footnote-reference info)
-      ;; match definition in `:footnotes-labels-alist'.
+	       'e-latex info))))
+    ;; Non-inline footnotes definitions are full Org data.
     (t
      (format "\\footnote{%s}"
 	     (org-trim
 	      (org-export-data
-		 (cdr (assoc label (plist-get info :footnotes-labels-alist)))
+	       (org-export-get-footnote-definition footnote-reference info)
-		 'latex info))))))))
+	       'e-latex info)))))))
 
 
 ;;;; Headline