Merge branch '10.4' into 10.5

include/my_alloc.h

@@ -25,6 +25,8 @@
 #define ALLOC_MAX_BLOCK_TO_DROP			4096
 #define ALLOC_MAX_BLOCK_USAGE_BEFORE_DROP	10
 
+#define ROOT_FLAG_READ_ONLY       4
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -50,11 +52,8 @@ typedef struct st_mem_root
      first free block in queue test counter (if it exceed 
      MAX_BLOCK_USAGE_BEFORE_DROP block will be dropped in 'used' list)
   */
-  unsigned int first_block_usage;
-
-#ifdef PROTECT_STATEMENT_MEMROOT
-  int read_only;
-#endif
+  unsigned short first_block_usage;
+  unsigned short flags;
 
   void (*error_handler)(void);