Macro SQLITE_DEBUG was set unconditionally, so both release build
modes had debugging enabled, including all asserts() and TESTCASE().
Move this macro definition under check if mode is Debug and fix all
warning which arised after disabling asserts().
Most of them are unused variables.

Since asserts were always disbled in src/box/sql.c, number
of issues were hidden. This patch enables asserts for mentioned
file by disabling set of NDEBUG in box/src/sqliteInt.h.
Also this patch fixes incorrect assertions about strlen() and
assertion that fieldno should always be less than format->field_count.
This assert is not always hold, e.g. for _schema space where max_id
is stored behind formatted fields.

Closes #3057

Add forgotten in previous commit regenerated box/sql/parse.c

Currently, only ALTER TABLE RENAME is supported in SQL. Ban
ALTER TABLE ADD COLUMN in the grammar until it is supported.
Corresponding issue submitted: #3075

Closes #2607

There're 3 places where FreeBSD specific routines
contained (for compatibility) unused parameters.
Mark them w/ unused attribute.

Closes #3037

SQLITE_ENABLE_UNLOCK_NOTIFY assumed to be always disabled.
SQLITE_OMIT_SHARED_CACHE assumed to be always enabled.

Deleted files
-------------

src/box/sql/notify.c
src/box/sql/btmutex.c

Deleted non-static functions
----------------------------

// btmutex.c
sqlite3BtreeEnter()
sqlite3BtreeLeave()
sqlite3BtreeHoldsMutex()
sqlite3BtreeEnterAll()
sqlite3BtreeLeaveAll()
sqlite3BtreeHoldsAllMutexes()
sqlite3SchemaMutexHeld()
sqlite3BtreeEnterCursor()
sqlite3BtreeLeaveCursor()

// btree.c
sqlite3BtreeLockTable()
sqlite3BtreeSharable()
sqlite3BtreeConnectionCount()

// notify.c
sqlite3_unlock_notify()
sqlite3ConnectionBlocked()
sqlite3ConnectionUnlocked()
sqlite3ConnectionClosed()

// vdbeaux.c
sqlite3VdbeEnter()
sqlite3VdbeLeave()

Deleted structure fields
------------------------

// btreeInt.h
struct Btree.wantToLock
struct Btree.lock
struct BtShared.nRef
struct BtShared.pNext
struct BtShared.pLock
struct BtShared.pWriter

// sqliteInt.h
struct sqlite3.pBlockingConnection
struct sqlite3.pUnlockConnection
struct sqlite3.pUnlockArg
struct sqlite3.xUnlockNotify
struct sqlite3.pNextBlocked

Deleted asserts
---------------

// common
assert(sqlite3BtreeHoldsAllMutexes(...))
assert(sqlite3SchemaMutexHeld(...))
assert(sqlite3BtreeHoldsMutex(...))

// btree.c
assert(... || sqlite3BtreeConnectionCount(...) > 0)
assert(p->wantToLock == 0 && p->locked == 0)
assert(hasSharedCacheTableLock(...))
assert(... || !hasReadConflicts(...))

Part of #2931

  There are some cases where a number of similar tests should be performed.
In this scenario, we had to write a lot of redundant symbols.

  The new method allows one to write the minimal number of code necessary for
tests.

This comit introduces a number of changes:

1. move a transaction state to fiber local struct

  This is important because the `sqlite3` is a shared structure and it was
used to store data related to the transaction. However it was working because
yield is called only on commit and it garanteed unique access. (With possible
effects on ddl.)

NOTE: `nDeferredCons` and `nDeferredImmCons` are stored in vdbe during vdbe
execution and moved to sql_txn when it needs to be saved until execution of the
next vdbe in the same transaction.

2. support savepoints

2.1. support abort (anonymous savepoints)

  Abort mechanism was simplified. Instead of storing track of all
savepoints without name, this commit introduces `anonymous_savepoint`.
  `anonymous_savepoint` is a structure which is stored in Vdbe and represents
the state of database on the beginning of the current statement. Tarantool
disallow multistatement, so a vdbe can have one statement max. That is why
having one savepoint is enough to perform abort.

2.2. named savepoints

Key points:
  - It uses Tarantool's savepoints
  - It allocates savepoints on the "region" (they are destroyed automatically)
  - There are some crutches around ddl (ddl should not be placed into a
transaction)

Closes #2989 #2931 #2964

The header is useless for Tarantool.

Fixes #2944.

There were dozen of test cases which still used ROWID feature.
Patch updates such cases.

Fixes #2884.

Rowid is removed right now from Tarantool SQL. That means that table
must have primary key. However, table defined w/o PK field caused
Tarantool to a crash instead of raising an error message complaining
missing PRIMARY KEY. Fix this and add a regression test

Closes #2929

Assign is_nullable property for each column in order to fix all sql
tests after reverting MP_NIL comparators in previous commit.

Closes #3009

This reverts commit a2f574e3.

After TableLock opcode removal, need to re-generate
opcode definitions file.

Removed OP_ParseSchema, OP_TableLock.
All other dead code connected to locking of open tables (for both
reading and writing) removed as well.
Remove auth.c file, it is not used anymore.

Few opcodes like OpenRead/OpenWrite exepcted 3rd argument to be DB
descriptor. Now there's a single DB backend and there's no need
for any descriptors. Remove from VDBE, fix code generator, update
opcode descriptions.

Closes #2855

  Make collation tokens obey ANSI ISO standard rules for identifiers.

Related to #2818

Closes #2653, #2121

  Thsis patch do two main changes:
  1. Delete SQLite's coll structure & replace it with Tarantool's
  2. Delere SQLite's create coll mechanism

  Tarantool can not easily support create collation mechanism of SQLite,
because collations must:
  - be persistent
  - be the same in tuple comparator and SQL Mem comparator
  Although new collations are limited, suggested ICU collations cover the
main set of use-cases. ICU supports:
  - Different locales & different strengths & other options...
  - Nimeruc stringths comparation.

  That is why we limit collation api at this point.

Part of #2121

  collation_list pragma should change as the way collations work changes.
To enumerate all collations one have to iterate space for now.

  This feature is required by SQL, because searching collations by name is
common operation there.

  Is implemented by creating extra hash table.

This is the second attempt to remove encodings.
At this point Tarantool SQL supports only UTF-8 encoding.

Part of #2295

Part of #2121

Deletion of rows from table (which is part of DROP TABLE procedure) is
wrapped in transaction now. If any Foreign Key violations occur, then
rollback transaction and halt execution of statement. Otherwise, commit
changes and continue DROP TABLE routine. This logic is implemented by
OP_FkCheckCommit opcode.
Added tests for this case.

Closes #2953

  There were analogies of those functions in Tarantool. This commit makes
SQL reuse them.
  All crutches (undef) are deleted.

Added new opcode OP_RenameTable, which implements
SQL statment: ALTER TABLE old_name RENAME TO new_name;
The main idea is to replace corresponding tuple in _space.
New tuple will contain new name and new SQL statement, which
creates this table. If it is parent table for foreign key,
update SQL statement of child table. Then, remove old name
from hash table and by calling callback function from VDBE,
update database schema with new table name. After all,
in the same way update triggers' statements in _trigger table,
if any exist.

Closes #2204

Closes #2506

Opcode OP_FCopy copies integer value of register P1 into
register P2. However, if third operand contains flag
OPFLAG_NOOP_IF_NULL and reg[P1] == NULL, then it does nothing.
It could lead to wrong behaviour, when reg[P2] is undefined:
in some cases VDBE uses reg[P2] instantly after OP_FCopy.
So, if reg[P2] is undefined, simply assign it to MEM_Null.

Closes #2949

Most tests are converted from original SQLite test suite.
Tests for DEFERRED constraint are not included since it is
currently broken and there is no opportunity to test it.

Applier must not update the replication lag upon receiving a packet
containing an error, because those packets don't have timestamps.

Closes #2965

Remove `message` field from blacklist, because JSON and plain
loggers are mutually exclusive.

Fixes #2923

    For some reason 'tnum' attribute for pk was set in convertToWithoutRowid
function, while for other indexes it was set in sqlite3CreateIndex. The if
clause in sqlite3CreateIndex was filtering not only PK, but inline unique
indexes too.

    Now 'tnum' is always set in sqlite3CreateIndex procedure.

Closes #2808

* Add pbkdf2 hashing API
* Wrapper of OpenSSL

Closes #2874