A fix and a test case for Bug#9359 "Prepared statements take snapshot

 of system vars at PREPARE time": implement a special Item
to handle system variables. This item substitutes itself with 
a basic constant containing variable value at fix_fields.


mysql-test/r/ps.result:
  - test results fixed (Bug#9359).
mysql-test/t/ps.test:
  - add a test case for Bug#9359 "Prepared statements take snapshot
   of system vars at PREPARE time"
sql/item_func.cc:
  - implement Item_func_get_system_var: we should not evaluate system
  variables in the parser, but instead should create an item which 
  is evaluated to a constant at execute.
  - remove an unused function
sql/item_func.h:
  Add a new item, Item_func_get_system_var
sql/mysql_priv.h:
  Move necessary declarations to make set_var.h objects visible in 
  item_func.h
sql/set_var.cc:
  - we should not print to network from get_system_var: if it's called
  from prepared statement prepare, we get packets out of order when using
  the binary protocol. Instead report the error to be sent to the user later.
  This is a backport from 5.0.
sql/set_var.h:
  - declaration of enum_var_type moved to mysql_priv.h

1 files changed, 0 insertions, 5 deletions

diff --git a/sql/set_var.h b/sql/set_var.h
index d452ba03367..2ac4fc2c260 100644
--- a/sql/set_var.h
+++ b/sql/set_var.h
@@ -30,11 +30,6 @@ class set_var;
 typedef struct system_variables SV;
 extern TYPELIB bool_typelib, delay_key_write_typelib, sql_mode_typelib;
 
-enum enum_var_type
-{
-  OPT_DEFAULT, OPT_SESSION, OPT_GLOBAL
-};
-
 typedef int (*sys_check_func)(THD *,  set_var *);
 typedef bool (*sys_update_func)(THD *, set_var *);
 typedef void (*sys_after_update_func)(THD *,enum_var_type);