org-src-get-lang-mode: Honor `major-mode-remap-alist'

* lisp/org-src.el (org-src-get-lang-mode): When `major-mode-remap' is
available, use it to honor `major-mode-remap-alist'.
* lisp/ox-html.el (org-html-fontify-code):
* lisp/ox-odt.el (org-odt-do-format-code): Use `org-src-get-lang-mode'.

lisp/org-src.el

@@ -970,11 +970,14 @@ Org-babel commands."
 (defun org-src-get-lang-mode (lang)
   "Return major mode that should be used for LANG.
 LANG is a string, and the returned major mode is a symbol."
-  (intern
-   (concat
-    (let ((l (or (cdr (assoc lang org-src-lang-modes)) lang)))
-      (if (symbolp l) (symbol-name l) l))
-    "-mode")))
+  (let ((mode (intern
+               (concat
+                (let ((l (or (cdr (assoc lang org-src-lang-modes)) lang)))
+                  (if (symbolp l) (symbol-name l) l))
+                "-mode"))))
+    (if (fboundp 'major-mode-remap)
+        (major-mode-remap mode)
+      mode)))
 
 (defun org-src-edit-buffer-p (&optional buffer)
   "Non-nil when current buffer is a source editing buffer.

lisp/ox-html.el

@@ -2368,8 +2368,7 @@ is the language used for CODE, as a string, or nil."
       (org-html-encode-plain-text code))
      (t
       ;; Map language
-      (setq lang (or (assoc-default lang org-src-lang-modes) lang))
-      (let* ((lang-mode (and lang (intern (format "%s-mode" lang)))))
+      (let* ((lang-mode (and lang (org-src-get-lang-mode lang))))
 	(cond
 	 ;; Case 1: Language is not associated with any Emacs mode
 	 ((not (functionp lang-mode))

lisp/ox-odt.el

@@ -3116,8 +3116,7 @@ and prefix with \"OrgSrc\".  For example,
 
 (defun org-odt-do-format-code
     (code info &optional lang refs retain-labels num-start)
-  (let* ((lang (or (assoc-default lang org-src-lang-modes) lang))
-	 (lang-mode (if lang (intern (format "%s-mode" lang)) #'ignore))
+  (let* ((lang-mode (if lang (org-src-get-lang-mode lang) #'ignore))
 	 (code-lines (org-split-string code "\n"))
 	 (code-length (length code-lines))
 	 (use-htmlfontify-p (and (functionp lang-mode)