Fix warnings.

include/typelib.h:
  Fix a compile warning. char *x is actually updated if
  it's found in the typelib (a peculiar way to return
  canonical value in case of a partial match)
mysys/typelib.c:
  Fix a warning.
sql/item_func.cc:
  Fix a compile-time warning.

include/typelib.h

@@ -26,7 +26,7 @@ typedef struct st_typelib {	/* Different types saved here */
   unsigned int *type_lengths;
 } TYPELIB;
 
-extern int find_type(const char *x, const TYPELIB *typelib,
+extern int find_type(char *x, const TYPELIB *typelib,
                      unsigned int full_name);
 extern void make_type(char *to,unsigned int nr,TYPELIB *typelib);
 extern const char *get_type(TYPELIB *typelib,unsigned int nr);

mysys/typelib.c

@@ -42,7 +42,7 @@
     >0  Offset+1 in typelib for matched string
 */
 
-int find_type(const char *x, const TYPELIB *typelib, uint full_name)
+int find_type(char *x, const TYPELIB *typelib, uint full_name)
 {
   int find,pos,findpos;
   reg1 my_string i;

sql/item_func.cc

@@ -5069,7 +5069,7 @@ Item_func_sp::init_result_field(THD *thd)
 {
   DBUG_ENTER("Item_func_sp::init_result_field");
 
-  LEX_STRING empty_name= { STRING_WITH_LEN("") };
+  LEX_STRING empty_name= { C_STRING_WITH_LEN("") };
   
   TABLE_SHARE *share;