- Adding a new grammar file sql_yacc_ora.yy, which is currently
  almost a full copy of sql_yacc.yy.

  Note, it's now assumed that sql_yacc.yy and sql_yacc_ora.yy
  use the same set of %token directives and exactly the same
  %union directive.
  These declarations should eventually be moved into a shared
  included file, to make sure that sql_yacc.h and sql_yacc_ora.h
  are compatible.

- Removing the "-p MYSQL" flag from cmake/bison.cmake, using
  the %name-prefix directive inside sql_yacc.yy and sql_yacc_ora.yy instead

- Adding other CMake related changes to build sql_yacc_ora.o
  form sql_yacc_ora.yy

- Adding NUMBER(M,N) as a synonym to DECIMAL(M,N) as the first
  Oracle compatibility syntax understood in sql_mode=ORACLE.

- Adding prototypes to functions add_virtual_expression()
  and handle_sql2003_note184_exception(), so they can be used
  in both sql_yacc.yy and sql_yacc_ora.yy.

- Adding a new test suite compat/oracle, with the first test "type_number".
  Use this:
   ./mtr compat/oracle.type_number   # to run a single test
   ./mtr --suite=compat/oracle       # to run the entire new suite

- Adding compat/oracle into the list of default suites,
  so BuildBot can run it automatically on pushes.