#9728 'Decreased functionality in "on duplicate key update
#8147 'a column proclaimed ambigous in INSERT ... SELECT .. ON DUPLICATE'
This ensures fields are uniquely qualified and also that one can't update other tables in the ON DUPLICATE KEY UPDATE part
The problem was that on Windows the access method indicates that access to file
such as "com1" and "lpt1" is allowed (since they are device names) and
this causes mysql to attempt to open them as databases or tables.
The fix was to write our own my_access method that uses other Win32 functions
to determine if the given argument is indeed a file and has to requested
mode.
