org.el: Prevent link activation in source code blocks

* org.el (org-in-fixed-width-region-p): Save match data.
(org-in-src-block-p): Use case-folding for searching the block
boundaries.
(org-activate-plain-links, org-activate-angle-links)
(org-activate-bracket-links): Prevent link activation in
source code blocks.

Thanks to Sébastien Vauban for reporting a related issue.

lisp/org.el

@@ -5295,12 +5295,13 @@ will be prompted for."
   "Run through the buffer and add overlays to links."
   (catch 'exit
     (let (f)
-      (when (re-search-forward (concat org-plain-link-re) limit t)
+      (when (and (re-search-forward (concat org-plain-link-re) limit t)
+		 (not (org-in-src-block-p)))
 	(org-remove-flyspell-overlays-in (match-beginning 0) (match-end 0))
 	(setq f (get-text-property (match-beginning 0) 'face))
-	(if (or (eq f 'org-tag)
-		(and (listp f) (memq 'org-tag f)))
-	    nil
+	(unless (or (org-in-src-block-p)
+		    (eq f 'org-tag)
+		    (and (listp f) (memq 'org-tag f)))
 	  (add-text-properties (match-beginning 0) (match-end 0)
 			       (list 'mouse-face 'highlight
 				     'face 'org-link
@@ -5439,7 +5440,8 @@ by a #."
 
 (defun org-activate-angle-links (limit)
   "Run through the buffer and add overlays to links."
-  (if (re-search-forward org-angle-link-re limit t)
+  (if (and (re-search-forward org-angle-link-re limit t)
+	   (not (org-in-src-block-p)))
       (progn
 	(org-remove-flyspell-overlays-in (match-beginning 0) (match-end 0))
 	(add-text-properties (match-beginning 0) (match-end 0)
@@ -5467,7 +5469,8 @@ by a #."
 
 (defun org-activate-bracket-links (limit)
   "Run through the buffer and add overlays to bracketed links."
-  (if (re-search-forward org-bracket-link-regexp limit t)
+  (if (and (re-search-forward org-bracket-link-regexp limit t)
+	   (not (org-in-src-block-p)))
       (let* ((help (concat "LINK: "
 			   (org-match-string-no-properties 1)))
 	     ;; FIXME: above we should remove the escapes.
@@ -18958,7 +18961,8 @@ See the individual commands for more information."
 
 (defsubst org-in-fixed-width-region-p ()
   "Is point in a fixed-width region?"
-  (eq 'fixed-width (org-element-type (org-element-at-point))))
+  (save-match-data
+    (eq 'fixed-width (org-element-type (org-element-at-point)))))
 
 (defun org-edit-special (&optional arg)
   "Call a special editor for the stuff at point.
@@ -20246,7 +20250,7 @@ and end of string."
   "Whether point is in a code source block.
 When INSIDE is non-nil, don't consider we are within a src block
 when point is at #+BEGIN_SRC or #+END_SRC."
-  (let (ov)
+  (let ((case-fold-search t) ov)
     (or (when (setq ov (overlays-at (point)))
 	  (memq 'org-block-background
 		(overlay-properties
@@ -20255,7 +20259,7 @@ when point is at #+BEGIN_SRC or #+END_SRC."
 	     (save-match-data
 	       (save-excursion
 		 (move-beginning-of-line 1)
-		 (looking-at ".*#\\+\\(BEGIN\\|END\\)_SRC")))))))
+		 (looking-at ".*#\\+\\(begin\\|end\\)_src")))))))
 
 (defun org-context ()
   "Return a list of contexts of the current cursor position.