client/mysql.cc:
  Don't use c_ptr() for cgets() and ensure buffer is not overwritten
mysql-test/r/cast.result:
  More test for CAST(0x.... as signed)
sql/opt_sum.cc:
  Fix bugs found during review
  - Changed code to be able to remove one if
  - Ensure that count == 0 only if is_exact_count == TRUE
sql/sql_delete.cc:
  Ensure 'allow_sum_func' is reset before call to setup_conds
sql/sql_lex.cc:
  allow_sum_func doesn't have to be reset for each query
  (It's to be reset in setup_fields() or before call to setup_conds()
sql/sql_load.cc:
  Move set of auto_increment_field_not_null so that it's not set if field value is NULL
sql/sql_prepare.cc:
  allow_sum_func doesn't have to be reset for each query
  (It's to be reset in setup_fields() or before call to setup_conds()
sql/sql_update.cc:
  Ensure 'allow_sum_func' is reset before call to setup_conds