Backport into MariaDB-5.2 the following:

WL#2474 "Multi Range Read: Change the default MRR implementation to implement new MRR interface"
WL#2475 "Batched range read functions for MyISAM/InnoDb"
        "Index condition pushdown for MyISAM/InnoDB"
Igor's fix from sp1r-igor@olga.mysql.com-20080330055902-07614:
  There could be observed the following problems:
  1. EXPLAIN did not mention pushdown conditions from on expressions in the 
  'extra' column.  As a result if a query had no where conditions pushed 
  down to a table, but had on conditions pushed to this table the 'extra' 
  column in the EXPLAIN for the table missed 'using where'.
  2. Conditions for ref access were not eliminated from on expressions 
  though such conditions were eliminated from the where condition.

storage/xtradb/include/row0mysql.h

@@ -564,6 +564,8 @@ struct mysql_row_templ_struct {
 #define ROW_PREBUILT_ALLOCATED	78540783
 #define ROW_PREBUILT_FREED	26423527
 
+typedef uint (*index_cond_func_t)(void *param);
+
 /* A struct for (sometimes lazily) prebuilt structures in an Innobase table
 handle used within MySQL; these are used to save CPU time. */
 
@@ -756,6 +758,14 @@ struct row_prebuilt_struct {
 	/*----------------------*/
 	UT_LIST_NODE_T(row_prebuilt_t)	prebuilts;
 					/* list node of table->prebuilts */
+	/*----------------------*/
+        index_cond_func_t idx_cond_func;/* Index Condition Pushdown function,
+                                        or NULL if there is none set */
+        void*           idx_cond_func_arg;/* ICP function  argument */
+        ulint           n_index_fields; /* Number of fields at the start of
+                                        mysql_template. Valid only when using
+                                        ICP. */
+	/*----------------------*/
 	ulint		magic_n2;	/* this should be the same as
 					magic_n */
 };