in the SELECT INTO OUTFILE clause starts with a special
character (one of n, t, r, b, 0, Z or N) and ENCLOSED BY
is empty, every occurrence of this character within a
field value is duplicated.

Duplication has been avoided.
New warning message has been added: "First character of
the FIELDS TERMINATED string is ambiguous; please use
non-optional and non-empty FIELDS ENCLOSED BY".


mysql-test/r/outfile_loaddata.result:
  BitKeeper file /home/uchum/work/bk/5.0-opt-31663/mysql-test/r/outfile_loaddata.result
  Added test case for bug #31663.
mysql-test/t/outfile_loaddata.test:
  BitKeeper file /home/uchum/work/bk/5.0-opt-31663/mysql-test/t/outfile_loaddata.test
  Added test case for bug #31663.
sql/sql_class.h:
  Fixed bug #31663.
  The select_export::is_ambiguous_field_term field has been added.
  This field is true if select_export::field_sep_char contains
  the first char of the FIELDS TERMINATED BY (ENCLOSED BY is empty),
  and items can contain this character.
  The select_export::field_term_char field has been added (first
  char of the FIELDS TERMINATED BY string or INT_MAX).
sql/sql_class.cc:
  Fixed bug #31663.
  The select_export::prepare method has been modified to calculate
  a value of the select_export::is_ambiguous_field_term field and
  to warn if this value is true.
  The select_export::send_data method has been modified to
  avoid escaping or duplication of the field_set_char if
  is_ambiguous_field_term is true.
sql/share/errmsg.txt:
  Fixed bug #31663.
  The ER_AMBIGUOUS_FIELD_TERM warning has been added.