variables

Bits higher than 2**31 were impossible to set on THD::options.  It's
probably a remnant from a time when options was a 32-bit integer.

Now, use unsigned long-long constants and variables to set and clear
THD::options.
---
Pulled comments back to column 49.


sql/mysql_priv.h:
  THD::options is an ulonglong, so we should define our bit constants 
  that way.
  ---
  Pulled comments back to column 49.
sql/set_var.h:
  THD::options is a ulonglong, and we if we're going to set bits higher
  than 2**31, then we must treat the bitmasks as a 64-bit number.