Bug 5501 - update with subquery using a view with an order by receives an error when using infinidb t

For some DML state, a context structure is not available when item->fix() is called for order by colu
When this happens, check to see if the information is available with another structure item_ptr and t
to resolve from there.
bug5518: Windows Port

removing sql/sql_builtin.cc from version control. It is rebuild by CMake
in Windows and by the build process in Linux. Because it's changed, it
can, and often does create automated pull problems.
bug5956: Error Code: 138 IDB-2015: Sorting length exceeded when using a view

Added checking in make_string_field function of item.cc. If thd is in VTABLE state
(infinidb query), or the table list contains InfiniDB tables, a varchar field is always created
instead of a blob field, even if the field length > CONVERT_IF_BIGGER_TO_BLOB.
Added session vars for the disk-based join stuff.
Bug 5881 - with replication, delete with idbpm(colname) in where clause failed with an error

Fixed typo.
Merge branch 'develop' of git://github.com/infinidb/mysql into develop
merge meta only: changes made by hand

Merge branch 'develop' into feature/MySQL-5.6