The lsof utility is prone to blocking on system calls that
it uses to obtain information about sockets (or files, devices,
etc.). This behavior is described in its own documentation.
It has a '-b' option (in combination with warnings suppression
via '-w') that reduces the probability of blocking, introducing
new problems (luckily probably not relevant for our use case).
However, there is no guarantee that it will not hang on some
distributions, with some TCP/IP stack implementations, or with
some filesystems, etc. Also, of the three utilities that are
suitable for our purposes, lsof is the slowest. So if there
are other utilities that we use during SST, such as 'ss' or
'sockstat', it is reasonable to use them instead of lsof.
This commit changes the prioritization of utilities, it does
not need additional tests (besides the numerous SST tests
already available in the galera suites). If the system still
need to use lsof, this commit adds the '-b' and '-w' options
to it command line - to reduce the likelihood of blocking.

Removed handling of the long-unsupported xtrabackup_pid file,
as it is not even created by modern versions of mariabackup.
Instead, added stopping of the asynchronous process that
mariabackup runs (if it is still active) to the exception
handler.

This commit makes the SST script for mariabackup more
resilient to unexpected terminations or hangs while
mariabackup or when SST scripts in a previous session
are still running (in reality they were hung while
waiting for something).

GCC 12.2.0 could issue -Wnonnull for an unreachable call to
strlen(new_path).  Let us prevent that by replacing the condition
(type == FILE_RENAME) with the equivalent (new_path).
This should also optimize the generated code, because the life time
of the parameter "type" will be reduced.

my_b_encr_write(): Initialize also block_length, and at the same time
last_block_length, so that all 128 bits can be initialized with fewer
writes. This fixes an error that was caught in the test
encryption.tempfiles_encrypted.

test_my_safe_print_str(): Skip a test that would attempt to
display uninitialized data in the test unit.stacktrace.
Previously, our CI did not build unit tests with MemorySanitizer.

handle_delayed_insert(): Remove a redundant call to pthread_exit(0),
which would for some reason cause MemorySanitizer in clang-19 to
report a stack overflow in a RelWithDebInfo build. This fixes a
failure of several tests.

Reviewed by: Vladislav Vaintroub

Emit a warning in the event that we finished processing input files
before reaching the boundary indicated by --stop-datetime.

Emit a warning in the event that we finished processing input files
before reaching the boundary indicated by --stop-position.

MDEV-31788 Factor functions to reduce duplication around spider_check_and_init_casual_read in ha_spider.cc

factored out static functions:
- spider_prep_loop
- spider_start_bg
- spider_send_queries

They are for unnecessary debugging purposes only.

The functions called in blocks protected by this macro remain
undefined as of 11.5 c96b23f9

It's virtually empty now

Show::Column() was added in MDEV-19772
4156b1a2

handler::pre_calculate_checksum was added in MDEV-16249
be5c432a

get_negated() was introduced in MDEV-16707

sql_cache was moved to lex in MDEV-11953 in
de745ecf

{STRING|INT|REAL|DECIMAL|DATE}_ITEM were replaced with CONST_ITEM in
MDEV-14630 c20cd68e

MDEV-16246 was fixed long ago. And this macro was removed in other
versions too

handler::need_info_for_auto_inc() was added in MDEV-7720 / MDEV-7726
in commit dc17ac16

This macro is unused, and not in 11.5 c96b23f9

This macro is unused

The flag argument was added to handler::start_bulk_insert() in
the MDEV-539 commit
ca2cdaad

new_data is const since at least 2017: a05a610d

handler has can_use_for_auto_inc_init() since at latest 2017:
dc17ac16

HA_EXTRA_USE_CMP_REF is undefined, and remains so as of 11.5
c96b23f9

HA_EXTRA_STARTING_ORDERED_INDEX_SCAN was added latest 2018:
921c5e93

net has thd since 2015 in 56aa1998 for MDEV-6152

arg_count was protected since 2015 in commit
afa17734