Part 5: EXIT statement

Adding unconditional EXIT statement:

  EXIT [ label ]

Conditional EXIT statements with WHERE clause
will be added in a separate patch.

Moving similar code from sql_yacc.yy and sql_yacc_ora.yy to methods:
  LEX::maybe_start_compound_statement()
  LEX::sp_push_loop_label()
  LEX::sp_push_loop_empty_label()
  LEX::sp_pop_loop_label()
  LEX::sp_pop_loop_empty_label()

The EXIT statement will also reuse this code.

Moving the code from *.yy to methods:
LEX::sp_change_context()
LEX::sp_leave_statement()
LEX::sp_iterate_statement()
to reuse the same code between LEAVE and ITERATE statements.
EXIT statement will also reuse the same code.

Part 9: EXCEPTION handlers

EXCEPTION is now supported in inner blocks.

When processing an SP body:

CREATE PROCEDURE p1 (parameters)
AS [ declarations ]
BEGIN statements
[ EXCEPTION exceptions ]
END;

the parser generates two "jump" instructions:
- from the end of "declarations" to the beginning of EXCEPTION
- from the end of EXCEPTION to "statements"

These jumps are useless if EXCEPTION does not exist.
This patch makes sure that these two "jump" instructions are
generated only if EXCEPTION really exists.

- Part 9: EXCEPTION handlers

  The top-most stored routine blocks now support EXCEPTION clause
  in its correct place:
  AS [ declarations ]
  BEGIN statements
  [ EXCEPTION exceptions ]
  END

  Inner block will be done in a separate commit.

- Part 14: IN OUT instead of INOUT (in SP parameter declarations)

Part 13: RETURN vs RETURNS in function definition:

  CREATE FUNCTION f1(a INT) RETURN INT ...

Part 12:  No parentheses if no arguments:

  CREATE FUNCTION f1 RETURN INT ...

Part 12: No parentheses if no arguments
Now "CREATE PROCEDURE p1 AS" is supported with no parentheses after the name.
Note, "CREATE FUNCTION f1 AS" is not supported yet, due to grammar conflict
with UDFs. Functions will be done in a separate patch.

Part 11: NULL as a statement

Part 10: Default variable value: x INT := 10;

Part 9: EXCEPTION handlers

- Adding exception handler syntax:
  WHEN exception_name THEN statement
- Adding EXCEPTION section intoi the top BEGIN..END SP block.
  Note, currently EXCEPTION goes in the beginning of the top BEGIN..END
  SP block.

TODO:
- add EXCEPTION section into inner blocks
- move EXCEPTION to the end of the block

Part 7: variable declarations

1. Adding const qualifiers into a few method parameters.

2. Adding methods:
- sp_label::block_label_declare()
- LEX::sp_block_init()
- LEX::sp_block_finalize()
  to share more code between the files sql_yacc.yy and sql_yacc_ora.yy,
  as well as between the rules sp_labeled_block, sp_unlabeled_block,
  sp_unlabeled_block_not_atomic.

3. sql_yacc.yy, sql_yacc_ora.yy changes:
- Removing sp_block_content
- Reorganizing the grammar so the rules sp_labeled_block,
  sp_unlabeled_block, sp_unlabeled_block_not_atomic now
  contain both BEGIN_SYM and END keywords. Previously,
  BEGIN_SYM and END resided in different rules.
  This change makes the grammar easier to read,
  as well as simplifies adding Oracle-style DECLARE section (coming soon):
    DECLARE
      ..
    BEGIN
      ..
    END;

  Good side effects:
  - SP block related grammar does not use Lex->name any more.
  - The "splabel" member was removed from %union

Adding:
  LEX::sp_variable_declarations_init()
  LEX::sp_variable_declarations_finalize()
  LEX::sp_handler_declaration_init()
  LEX::sp_handler_declaration_finalize()
  LEX::sp_declare_cursor()
  sp_context::declare_condition()

In the affected test chunk in sp.test, sql_mode is set to 0xFFFFFFFF,
which includes ORACLE, therefore an additional "AS" keyword is required:

  CREATE PROCEDURE p1() AS BEGIN END;

Part 4: AS/IS keyword before a function or a procedure body

Part6: assignment operator

  var:= 10;

Part2: Different order of IN, OUT, INOUT keywords in CREATE PROCEDURE params

Changing label syntax from "label:" to "<<label>>".

Based on the patch by Dmitry Tolpeko.

Reusing sp_create_assignment_lex() and sp_create_assignment_lex() in
sql_yacc.yy and sql_yacc_ora.yy

Reusing THD::parse_error() in sql_yacc.yy and sql_yacc_ora.yy

- 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.

buf_load(): When the file cannot be opened for reading, issue a note,
not an error message.

debug build with older cmake.

The constant is implicitely defined by VS when chosen C runtime is Debug
(/MTd, MDd).

CMake does not define it since https://public.kitware.com/Bug/view.php?id=15777
was fixed.

We remove it from compile flags, to be able to build Debug with /MT runtime
using older cmakes.

Also  do not use BUILD_BYPRODUCTS in ExternalPeoject for older cmake

The patch actually fixes the old defect of the optimizer that
could not extract keys for range access from IN predicates
with row arguments.

This problem was resolved in the mysql-5.7 code. The patch
supersedes what was done there:
 - it can build range access when not all components of
 the first row argument are refer to the columns of the table
 for which the range access is constructed.
 - it can use equality predicates to build range access
 to the table that is not referred to in this argument.

Also, some MDEV-11738/MDEV-11581 post-push fixes.

In MariaDB 10.1, there is no fil_space_t::is_being_truncated field,
and the predicates fil_space_t::stop_new_ops and fil_space_t::is_stopping()
are interchangeable. I requested the fil_space_t::is_stopping() to be added
in the review, but some added checks for fil_space_t::stop_new_ops were
not replaced with calls to fil_space_t::is_stopping().

buf_page_decrypt_after_read(): In this low-level I/O operation, we must
look up the tablespace if it exists, even though future I/O operations
have been blocked on it due to a pending DDL operation, such as DROP TABLE
or TRUNCATE TABLE or other table-rebuilding operations (ALTER, OPTIMIZE).
Pass a parameter to fil_space_acquire_low() telling that we are performing
a low-level I/O operation and the fil_space_t::is_stopping() status should
be ignored.