gcc_sync.h, solaris.h, generic-msvc.h copied verbatim.

Status variables added: Table_open_cache_hits, Table_open_cache_misses,
Table_open_cache_overflows.

System variables added: table_open_cache_active_instances (read-only).

The intent of this patch is to avoid copying arguments from
a pair "Item **args, uint arg_count" to List<Item> in
sp_head::execute_function(). If the number of a stored function parameters
is huge, such copying can affect performance.

Change:
1. Adding a new method Row_definition_list::adjust_formal_params_to_actual_params,
   which accepts a pair of "Item **, uint".
2. Modifying the code to use the new method:
   - the calls for sp_rcontext::retrieve_field_definitions() and
     Row_definition_list::adjust_formal_params_to_actual_params() have
     been moved from sp_rcontext::create() to sp_head::rcontext_create(),
     to handle different argument notations easier (Item** vs List<Item>).
   - sp_rcontext::create() now assumes that the passed Row_definition_list
     is already adjusted to the actual SP parameters, and all "TYPE OF"
     and "ROWTYPE OF" references are resolved.
3. Removing creation of List<Item> in sp_head::execute_procedure(),
   using the code with "Item**, uint" notation instead.
4. Improvement of the code for MDEV-10577:
   As a good side effect, this patch gets rid of double security context
   switch inside sp_head::execute_trigger():
   sp_rcontext is created when the context is already switched,
   so the second context switch inside sp_head::rcontext_create() was
   redundant. This is solved by adding a "bool switch_secutiry_ctx" parameter
   to rcontext_create(), so now execute_function() and execute_procedure()
   pass "true", while execute_trigger() passes "false".

Moving a few methods from sp_rcontext to different classes:

- Table_ident::resolve_table_rowtype_ref
- Qualified_column_ident::resolve_type_ref
- Row_definition_list::resolve_table_rowtype_ref
- Row_definition_list::adjust_formal_params_to_actual_params

It easier to reuse these methods this way in the future.

- The line was accidently removed by dd8474b1
- The effect of the missing test was just a few extra malloc when creating
  internal temporary tables. Nothing critical, but better got get fixed.

Update.rdiff fle

Also, introduce my_popen()/my_fgets() wrapper function for popen()/fgets()
in mysqltest to workaround a popen() bug in Windows C runtime,
mentioned in MDEV-9409

This workaround was used previously for "exec". From now on, it is also
used are used also for "perl" snippets.

MDEV-13919 sql_mode=ORACLE: Derive length of VARCHAR SP parameters with no length from actual parameters

reapply 6192f0bf

TSAN warnings count decreased from 206 to 195

- Clean up formulas and comments for host_cache_size and back_log
- Added test of autoset (for host_cache_size)
- Marked open_files_limit as auto_set

Ensure that no adaptive hash index exists for any system tables,
so that the blocked TRUNCATE TABLE t1 will not block the concurrent
TRUNCATE TABLE t2.

Made a few links in README.md secure (https).

This bug is a regression caused by the code refactoring in
commit f5a833c3. It was not present
in any release of the MariaDB server. The bug affects table-rebuilding
ALTER TABLE when the source table is in ROW_FORMAT=REDUNDANT and
contains no virtual columns.

row_log_table_low_redundant(): Log virtual column data only if
virtual columns are present.

The issue was that r_loops, r_rows and r_filtered in ANALYZE FORMAT= JSON were not
calculated for the table on which we were performing the MRR scan in the BKA join
Fixed this by adding respective counter in the JOIN_TAB_SCAN_MRR::open and JOIN_TAB_SCAN_MRR::next

The problem is there is an overflow for the key_file_length.
Added the maximum limit for the key_file_length

The ALTER TABLE…IMPORT TABLESPACE adjustment code that was introduced by
WL#5522 in MySQL 5.6 is incorrectly invoking rec_get_status() on a
ROW_FORMAT=REDUNDANT record to determine if a record is a leaf page record.
The function rec_get_status(rec) is only to be called on
ROW_FORMAT=COMPACT, DYNAMIC or COMPRESSED records.

3-argument form of DATE_FORMAT