Split item->flags into base_flags and with_flags

This was done to simplify copying of with_* flags

Other things:
- Changed Flags to C++ enums, which enables gdb to print
  out bit values for the flags. This also enables compiler
  errors if one tries to manipulate a non existing bit in
  a variable.
- Added set_maybe_null() as a shortcut as setting the
  MAYBE_NULL flags was used in a LOT of places.
- Renamed PARAM flag to SP_VAR to ensure it's not confused with persistent
  statement parameters.

1 files changed, 2 insertions, 2 deletions

diff --git a/sql/sql_view.cc b/sql/sql_view.cc
index 11ee44d5c5f..ee698e51243 100644
--- a/sql/sql_view.cc
+++ b/sql/sql_view.cc
@@ -137,7 +137,7 @@ bool check_duplicate_names(THD *thd, List<Item> &item_list, bool gen_unique_view
     Item *check;
     /* treat underlying fields like set by user names */
     if (item->real_item()->type() == Item::FIELD_ITEM)
-      item->flags&= ~ITEM_FLAG_IS_AUTOGENERATED_NAME;
+      item->base_flags&= ~item_base_t::IS_AUTOGENERATED_NAME;
     itc.rewind();
     while ((check= itc++) && check != item)
     {
@@ -566,7 +566,7 @@ bool mysql_create_view(THD *thd, TABLE_LIST *views,
     while ((item= it++, name= nm++))
     {
       item->set_name(thd, *name);
-      item->flags&= ~ITEM_FLAG_IS_AUTOGENERATED_NAME;
+      item->base_flags&= ~item_base_t::IS_AUTOGENERATED_NAME;
     }
   }