Adding symbol FN_DIRSEP to Windows as well.

Fixing test case that fails on Windows because .dll is used.

When installing plugins, there is a missing check
for slash (/) in the path on Windows. Note that on
Windows, both / and \ can be used to separate
directories.

This patch fixes the issue by:
- Adding a FN_DIRSEP symbol for all platforms
  consisting of a string of legal directory
  separators.
- Adding a charset-aware version of strcspn().
- Adding a check_valid_path() function that uses
  my_strcspn() to check if any FN_DIRSEP character
  is in the supplied string.
- Using the check_valid_path() function in
  sql_plugin.cc and sql_udf.cc (which means
  replacing the existing test there).

include/config-netware.h:
  Adding FN_DIRSEP
  ******
  Adding FN_DIRSEP
include/config-win.h:
  Adding FN_DIRSEP
  ******
  Adding FN_DIRSEP
include/m_ctype.h:
  Adding my_strspn() and my_strcspn().
  
  ******
  Adding my_strspn() and my_strcspn().
include/my_global.h:
  Adding FN_DIRSEP
  ******
  Adding FN_DIRSEP
mysql-test/t/plugin_not_embedded.test:
  Adding test that file names containing / is
  disallowed on *all* platforms.
  ******
  Adding test that file names containing / is
  disallowed on *all* platforms.
sql/sql_plugin.cc:
  Introducing check_if_path() function for
  checking if filename is a path to include
  / on Windows.
  ******
  Introducing check_if_path() function for
  checking if filename is a path to include
  / on Windows.
sql/sql_udf.cc:
  Switching to use check_if_path() function.
  ******
  Switching to use check_if_path() function.
strings/my_strchr.c:
  Adding my_strspn() and my_strcspn().
  ******
  Adding my_strspn() and my_strcspn().

This is a code cleanup.

The implementation of a storage engine (subclasses of handler) is not supposed
to call my_error() directly inside the engine implementation, 
but only return error codes, and report errors later at the demand
of the sql layer only (if needed), using handler::print_error().

This fix removes misplaced calls to my_error(),
and provide an implementation of print_error() instead.

Given that the sql layer implementation of create table, ha_create_table(),
does not use print_error() but returns ER_CANT_CREATE_TABLE directly,
the return code for create table statements using the performance schema
has changed to ER_CANT_CREATE_TABLE.

Adjusted the test suite accordingly.

Before this fix, the test thread_cache failed with spurious failures.

The test used:
-- disconnect X
-- connect Y

while assuming that connection Y would reuse connection X slot in the thread cache.

For this to happen, the disconnect X operation must be given enough time to complete,
otherwise connect Y can be executed in the server before X actually finishes.

This fix uses wait conditions to make the test execution more controlled,
and more reproductible.

Before this fix, the test myisam_file_io executed:
- (a) an update on setup_instrument to disable non myisam file io instruments
- (b) a truncate on events_waits_history_long
and later
- (c) a select on events_waits_history_long

Surprisingly, events that were supposed to be disabled in (a) and removed in (b)
still were found in (c).

This happened for events such as 
  wait/io/file/innodb/innodb_data_file fil0fil.c: sync  
because the sync was started before (a) and completed after (b),
and as a consequence was added in the performance schema history, as expected.

Presence of these records in the history made the test fail. 

This fix makes the test script more robust to account for extra spill waits records in (c).

This fix affects the test suite only.

Before this fix, performance schema tests dml_*.test could
fail with spurious failure, depending on the table content.

This fix simplifies the SELECT tests in the dml_*.test scripts,
to only verify that the SELECT operation passed the security checks
and succeeded, which was the original intent of the test.

Usage of 
  --replace_column 1 # 2 # 3 # 4 # ...
to discard the test output was replaced by a simpler and more maintainable 
  --disable_result_log
which also work for empty tables.

Fixing the testcase to use the database name
as connected_db instead of 'test' database.

mysql-test/r/mysql.result:
  Additional fix in the test for bug#54899.
mysql-test/t/mysql.test:
  Additional fix in the test for bug#54899.

The problem was due to a misuse of GCC asm constraints used to
implement a atomic load. On x86_64, the load was implemented
as a cmpxchg which implicitly uses the eax register as a
source and destination operand, yet the dummy value used for
comparison wasn't being properly loaded into eax (and other
problems).

The core problem is that cmpxchg is unnecessary as a load
on x86_64 as there are other simpler instructions such
as xadd. Even though, such instructions are only used to
have a memory barrier as load and stores are atomic by
definition. Hence, the solution is to explicitly issue the
required CPU and compiler barriers.

include/atomic/x86-gcc.h:
  Issue a synchronizing instruction before loading the value.
  Afterwards, issue a compiler barrier to prevent reordering.

integral type. Use intptr which is designed to hold pointer values
and pass it to off_t.

mysys/stacktrace.c:
  Add a compile time assert to ensure that off_t is large enough
  to hold the pointer value.

metadata"

Improved error handling such that queries against Information_Schema.Tables won't
fail if a federated table can't make a remote connection.

mysql-test/r/lock_multi.result:
  Updated with warnings that were previously masked.
mysql-test/r/mdl_sync.result:
  Updated with warnings that were previously masked.
mysql-test/r/merge.result:
  Updated with warnings that were previously masked.
mysql-test/r/show_check.result:
  Updated with warnings that were previously masked.
mysql-test/r/view.result:
  Updated with warnings that were previously masked.
mysql-test/suite/federated/federated_bug_35333.result:
  New test results for bug#35333
mysql-test/suite/federated/federated_bug_35333.test:
  New test or bug#35333
sql/sql_show.cc:
  If get_schema_tables_record() encounters an error, push a warning,
  set the TABLE COMMENT column with the error text, and clear the
  error so that the operation can continue.

the DROP statement ..."
      
Problem: When using temporary tables and closing a session, an
implicit DROP TEMPORARY TABLE IF EXISTS is written to the binary
log (while cleaning up the context of the session THD - see:
sql_class.cc:THD::cleanup which calls close_temporary_tables).
     
close_temporary_tables, first checks if the binary log is opened
and then proceeds to creating the DROP statements. Then, such
statements, are written to the binary log through
MYSQL_BIN_LOG::write(Log_event *). Inside, there is another check
if the binary log is opened and if not an error is returned. This
is where the faulty behavior is triggered. Given that the test
case replays a binary log, with temp tables statements, and right
after it issues RESET MASTER, there is a chance that is_open will
report false (when the mysql session is closed and the temporary
tables are written).
      
is_open may return false, because MYSQL_BIN_LOG::reset_logs is
not setting the correct flag (LOG_CLOSE_TO_BE_OPENED), on the
MYSQL_LOG_BIN::log_state (instead it sets just the
LOG_CLOSE_INDEX flag, leaving the log_state to
LOG_CLOSED). Thence, when writing the DROP statement as part of
the THD::cleanup, the thread could get a return value of false
for is_open - inside MYSQL_BIN_LOG::write, ultimately reporting
that it can't write the event to the binary log.
      
Fix: We fix this by adding the correct flag, missing in the
second close.

mysql-test/r/show_check.result:
  Fixed corrupted result file

metadata"
            
Improved error handling such that queries against Information_Schema.Tables won't
fail if a federated table can't make a remote connection.

mysql-test/r/merge.result:
  Updated with warnings that were previously masked.
mysql-test/r/show_check.result:
  Updated with warnings that were previously masked.
mysql-test/r/view.result:
  Updated with warnings that were previously masked.
sql/sql_show.cc:
  If get_schema_tables_record() encounters an error, push a warning,
  set the TABLE COMMENT column with the error text, and clear the
  error so that the operation can continue.

Improved error handling such that queries against Information_Schema.Tables won't
fail if a Federated table is unable to connect to remote host.



sql/sql_show.cc:
  If Handler::Info() fails, save error text in TABLE COMMENTS column, clear error.

will not display "indicated result file not found" due to wrongly named
var directory.

It is not necessary to support INSERT DELAYED for a single value insert,
while we do not support that for multi-values insert when binlog is
enabled in SBR.

The lock_type is upgrade to TL_WRITE from TL_WRITE_DELAYED for
INSERT DELAYED for single value insert as multi-values insert
did when binlog is enabled. Then it's safe. And binlog it as
INSERT without DELAYED.

mysql-test/extra/binlog_tests/binlog_insert_delayed.test:
  Added test case for bug#57666.
mysql-test/suite/binlog/r/binlog_row_binlog.result:
  Updated for bug#57666
mysql-test/suite/binlog/r/binlog_statement_insert_delayed.result:
  Updated for bug#57666
mysql-test/suite/binlog/r/binlog_stm_binlog.result:
  Updated for bug#57666
mysql-test/suite/rpl/r/rpl_stm_insert_delayed.result:
  Updated for bug#57666
sql/sql_insert.cc:
  Updated code for the following things:
  1. Upgrade the lock_type to TL_WRITE from TL_WRITE_DELAYED
  for INSERT DELAYED for single value insert as multi-values
  insert did when binlog is enabled.
  2. Clear code to not binlog INSERT DELAYED STMT in SBR.
  3. Get rid of privilege check for log_on.