When linking Perl DBD::ODBC with the ODBC-ODBC Bridge on FreeBSD I get wchar.h errors. What should I do?

When linking the ODBC-ODBC Bridge with Perl DBD::ODBC, you may get the following error:

/usr/local/easysoft/oob/client/include/sql.h:46,
from
/usr/local/easysoft/oob/client/include/sqlext.h:46,
from dbdodbc.h:9,
from ODBC.h:9,
from ODBC.xs:1:
/usr/local/easysoft/oob/client/include/sqltypes.h:14: wchar.h: No such file or directory

To solve this, comment out any references to wchar.h in /usr/local/easysoft/oob/client/include/sqlext.h.