Fix compilation error with Bison >=2.6

Because of the way newer Bison versions arrange the prototypes in the generated header files, there will be a compiler error because of inconsistent prototypes if YYPARSE_PARAM is used.  Move #define of YYPARSE_PARAM into header file so that the prototype for orafce_sql_yyparse() is consistent.

See also http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=710633.