This is a backport of the patch for MDEV-9653 (fixed earlier in 10.1.13).

The code in Item_func_case::fix_length_and_dec() did not
calculate max_length and decimals properly.

In case of any numeric result (DECIMAL, REAL, INT) a generic method
Item_func_case::agg_num_lengths() was called, which could erroneously result
into a DECIMAL item with max_length==0 and decimals==0, so the constructor of
Field_new_decimals tried to create a field of DECIMAL(0,0) type,
which caused a crash.

Unlike Item_func_case, the code responsible for merging attributes in
Item_func_coalesce::fix_length_and_dec() works fine: it has specific execution
branches for all distinct numeric types and correctly creates a DECIMAL(1,0)
column instead of DECIMAL(0,0) for the same set of arguments.

The fix does the following:
- Moves the attribute merging code from Item_func_coalesce::fix_length_and_dec()
  to a new method Item_func_hybrid_result_type::fix_attributes()
- Removes the wrong code from Item_func_case::fix_length_and_dec()
  and reuses fix_attributes() in both Item_func_coalesce::fix_length_and_dec()
  and Item_func_case::fix_length_and_dec()
- Fixes count_real_length() and count_decimal_length() to get an array
  of Items as an argument, instead of using Item::args directly.
  This is needed for Item_func_case::fix_length_and_dec().
- Moves methods Item_func::count_xxx_length() from "public" to "protected".
- Removes Item_func_case::agg_num_length(), as it's not used any more.
- Additionally removes Item_func_case::agg_str_length(),
  as it also was not used (dead code).

SHOW PROCESSLIST output can be affected by not completed concurrent queries.
Removed this affected SHOW PROCESSLIST since it doesn't seem to affect original
problem.

Fixed wait condition in test case to actually wait for get_lock() completion
(not for lock acquisition as it was before). This removes sporadic extra row in
subsequent processlist queries.

Item_func_ifnull::date_op() and Item_func_coalesce::date_op() could
erroneously return 0000-00-00 instead of NULL when get_date()
was called with the TIME_FUZZY_DATES flag, e.g. from LEAST().

5.5 part of the fix

don't allocate all the stack, leave some stack for
function calls.

To test I added the following line:
  alloca_size = available_stack_size() - X
at X=4096 or less mysqld crashed, at 8192 mtr test passed.

remove erroneous free() call

The test created a file in location relative to the datadir
(a few levels above datadir).
The file was created by MariaDB server (via INTO OUTFILE), and
later removed by mysqltest (via remove_file). The problem is that
when the vardir is a symlink, MariaDB server and mysqltest can
resolve such paths differently. MariaDB server would return back
to where the symlink is located, while mysqltest would go above
the real directory. For example, if the test is run with --mem,
and /bld/5.5/mysql-test/var points at /dev/shm/var_auto_X, then
SELECT INTO OUTFILE created a file in /bld/5.5/mysql-test , but
remove_file would look for it in /dev/shm/.

The test is re-written so that all paths are resolved in perl,
the logic itself hasn't changed.

Debian tests are run in 2017, update the test to
use 2027 as a "future".

don't use ipv6 is the check fails for any reason. for example, an
ancient solaris perl didn't have sockaddr_in6() in Socket at all.

it caused feedback plugin tests to fail

1. ignore generated dtrace files
2. don't rewrite probes_mysql_nodtrace.h in-place

1. check that unused inline functions are removed
2. only allow compilation if they are or if the check if overridden
3. with CMAKE_GENERATOR=Makefiles, use all flags when testing
   (e.g. both CMAKE_C_FLAGS and CMAKE_C_FLAGS_DEBUG if
   CMAKE_BUILD_TYPE=Debug). This is because
 - on Solaris with the SunPro compiler, default CMAKE_C_FLAGS_xxx
   values contain -xO2 (for Release and RelWithDebInfo)
   and -g (for RelWithDebInfo and Debug)
 - proper inlining only works at -xO4 without -g
 - so if CMAKE_C_FLAGS has -xO4, inlining would work in
   configure.cmake (before this fix) and fail during actual compilation

also remove the outdated check for inline from myu_global.h

1. unused static inline functions are only removed at -xO4,
   otherwise test binaries will depend on various mysys
   symbols that they don't use. Link test with libmysys.

2. Sphinx - don't instantiate (explicitly) templates before
   they're defined. Or, rather, don't instantiate them explicitly at
   all.

3. GIS - don't use anonymous unions and structs.

In case of missing includedir file, we would attempt to free a NULL
pointer. Make sure to guard against that.

In the case of error during my_load_defaults, we would not free the
args array.

Fix test failure when using maria small-block size. We need to query
the max_key_length and max_key_parts based on the the tmp table engine.

MDEV-7765: Crash (Assertion `!table || (!table->write_set || bitmap_is_set(table->write_set, field_index) || bitmap_is_set(table->vcol_set, field_index))' fails) on using function over not created table

Problem was that created table was not marked as used (not set query_id) and so opening tables for stored function pick it up (as opened place holder for it) and used changing TABLE internals.

The select mentioned in the bug attempted to create a temporary table
using the maria storage engine. The table needs to have primary keys such that
duplicates can be removed. Unfortunately this use case has a longer
than allowed key and the tmp table got created without a temporary key.
We must not allow materialization for the subquery if the total key
length and key parts is greater than what the storage engine supports.

5.5.47-37.7

test case for ALTER TABLE view CHECK PARTITION

test case

Correct fix. Generate the query in the client charset,
not in the system one.

reverted about half of commits as either not applicable or
outright wrong

        The http-proxy option to the FEEDBACK plugin backported.

When one evaluates row-based comparison like (X, Y) = (A,B), one should
first call bring_value() for the Item that returns row value. If you
don't do that and just attempt to read values of X and Y, you get stale
values.
Semi-join/Materialization can take a row-based comparison apart and
make ref access from it. In that case, we need to call bring_value()
to get the index lookup components.

Consider a query with subquery in form t.key=(select ...). Suppose, the
parent query uses this equality for ref access.
It will attempt to evaluate the subquery in get_best_combination(),
right before the join->join_tab[...] array is filled.  The problem was
that subquery optimization will attempt to look at parent's join->join_tab
to check how many times subquery will be executed (and crash).

Fixed by not doing that when the subquery is constant (non-constant
subqueries are only be evaluated during join execution, so they are not
affected)

cherry-pick f1daf9ce from 10.0 branch
-------------------------------------

Fix build failures caused by new C runtime library
- isnan, snprintf, struct timespec are now defined, attempt to
redefine them leads
- P_tmpdir, tzname are no more defined
-  lfind() and lsearch() in lf_hash.c had to be renamed,  declaration
conflicts with some C runtime functions with the same name declared in
a header included by stdlib.h

 Also fix couple of annoying warnings :
- remove #define NOMINMAX from config.h to avoid "redefined" compiler
warnings(NOMINMAX is already in compile flags)

- disable incremental linker in Debug as well (feature not used much
and compiler crashes often)

Also simplify package building with Wix, require Wix 3.9 or later
(VS2015 is not compatible with old Wix 3.5/3.6)

fix dynstr_append_os_quoted() to escape single quotes correctly
for a POSIX shell

and a trivial cleanup to avoid manually-specified lengths

Fixed adding derived tables items to outer one.

mysqlcheck tool can be used even if opt_systables_only is true
(to upgrade views from mysql - that overrides opt_systables_only)