Fix problem with a missing function in XEmacs

`latexenc-coding-system-to-inputenc' does not seem to be available in XEmacs.

lisp/ChangeLog

@@ -4,6 +4,8 @@
 	author line.
 	(org-export-latex-fontify-headline): Allow several arguments, not
 	just one.
+	(org-export-latex-fix-inputenc): Catch the error when
+	`latexenc-coding-system-to-inputenc' is not defined.
 
 	* org-agenda.el (org-agenda-skip-if-todo): New function.
 	(org-agenda-skip-if): Add conditions for TODO keywords.

lisp/org-latex.el

@@ -2128,7 +2128,8 @@ The conversion is made depending of STRING-BEFORE and STRING-AFTER."
 (defun org-export-latex-fix-inputenc ()
   "Set the codingsystem in inputenc to what the buffer is."
   (let* ((cs buffer-file-coding-system)
-	 (opt (or (latexenc-coding-system-to-inputenc cs) "utf8")))
+	 (opt (or (ignore-errors (latexenc-coding-system-to-inputenc cs))
+		  "utf8")))
     (when opt
       ;; Translate if that is requested
       (setq opt (or (cdr (assoc opt org-export-latex-inputenc-alist)) opt))