Ensure VALGRIND_MALLOCLIKE_BLOCK protects the red zones.

* Redzones for custom alloc were not protected by VALGRIND_MALLOCLIKE_BLOCK.
  mc_main.c client request handling completed with protection
  of the redzones.
* custom_alloc.c test modified to test this case.
* mc_errors.c modified so as to first search for a malloc-ed block
  bracketting the error : for a custom allocator, a recently freed
  block can have just been re-allocated.
  In such a case, describing the address (e.g. in case of error)
  points to the block freed rather than to the block just allocated.
  If there is *also* a recently freed block bracketting the address,
  the block description is changed to indicate that.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12439 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/NEWS b/NEWS
index 9e8d0c5..f2a65c7 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,10 @@
   - Addition of GDB server monitor command 'who_points_at' that lists
     the locations pointing at a block.
 
+  - if a redzone size > 0 is given, VALGRIND_MALLOCLIKE_BLOCK now
+    will detect an invalid access of these redzones, by marking them
+    noaccess.
+
 * ==================== OTHER CHANGES ====================
 
 * The C++ demangler has been updated so as to work well with C++