mdbx: release v0.12.1 (Positive Proxima)

The planned frontward release with new superior features on the day of 20 anniversary of [Positive Technologies](https://ptsecurty.com).

New:
----

 - The `Big Foot` feature which significantly reduces GC overhead for processing large lists of retired pages from huge transactions.
   Now _libmdbx_ avoid creating large chunks of PNLs (page number lists) which required a long sequences of free pages, aka large/overflow pages.
   Thus avoiding searching, allocating and storing such sequences inside GC.
 - Improved hot/online validation and checking of database pages both for more robustness and performance.
 - New solid and fast method to latch meta-pages called `Troika`.
   The minimum of memory barriers, reads, comparisons and conditional transitions are used.
 - New `MDBX_VALIDATION` environment options to extra validation of DB structure and pages content for carefully/safe handling damaged or untrusted DB.
 - Accelerated ×16/×8/×4 by AVX512/AVX2/SSE2/Neon implementations of search page sequences.
 - Added the `gcrtime_seconds16dot16` counter to the "Page Operation Statistics" that accumulates time spent for GC searching and reclaiming.
 - Copy-with-compactification now clears/zeroes unused gaps inside database pages.
 - The `C` and `C++` APIs has been extended and/or refined to simplify using `wchar_t` pathnames.
   On Windows the `mdbx_env_openW()`, `mdbx_env_get_pathW()`, `mdbx_env_copyW()`, `mdbx_env_open_for_recoveryW()` are available for now,
   but the `mdbx_env_get_path()` has been replaced in favor of `mdbx_env_get_pathW()`.
 - Added explicit error message for Buildroot's Microblaze toolchain maintainers.
 - Added `MDBX_MANAGE_BUILD_FLAGS` build options for CMake.
 - Speed-up internal `bsearch`/`lower_bound` implementation using branchless tactic, including workaround for CLANG x86 optimiser bug.
 - A lot internal refinement and micro-optimisations.
 - Internally counted volume of dirty pages (unused for now but for coming features).

Fixes:
------

 - Never use modern `__cxa_thread_atexit()` on Apple's OSes.
 - Don't check owner for finished transactions.
 - Fixed typo in `MDBX_EINVAL` which breaks MingGW builds with CLANG.

37 files changed, 7604 insertions(+), 7417 deletions(-)
Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>

ChangeLog.md

@@ -1,37 +1,42 @@
 ChangeLog
 ---------
 
-## v0.12.1 (Positive Proxima) scheduled to 2022-08-24
+## v0.12.1 (Positive Proxima) at 2022-08-24
 
 The planned frontward release with new superior features on the day of 20 anniversary of [Positive Technologies](https://ptsecurty.com).
 
+```
+37 files changed, 7604 insertions(+), 7417 deletions(-)
+Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>
+```
+
 New:
 
  - The `Big Foot` feature which significantly reduces GC overhead for processing large lists of retired pages from huge transactions.
    Now _libmdbx_ avoid creating large chunks of PNLs (page number lists) which required a long sequences of free pages, aka large/overflow pages.
    Thus avoiding searching, allocating and storing such sequences inside GC.
  - Improved hot/online validation and checking of database pages both for more robustness and performance.
+ - New solid and fast method to latch meta-pages called `Troika`.
+   The minimum of memory barriers, reads, comparisons and conditional transitions are used.
  - New `MDBX_VALIDATION` environment options to extra validation of DB structure and pages content for carefully/safe handling damaged or untrusted DB.
- - Optionally cache for pointers to last/steady meta-pages (currently is off by default).
+ - Accelerated ×16/×8/×4 by AVX512/AVX2/SSE2/Neon implementations of search page sequences.
  - Added the `gcrtime_seconds16dot16` counter to the "Page Operation Statistics" that accumulates time spent for GC searching and reclaiming.
  - Copy-with-compactification now clears/zeroes unused gaps inside database pages.
- - The C++ API has been refined to simplify support for `wchar_t` in path names.
+ - The `C` and `C++` APIs has been extended and/or refined to simplify using `wchar_t` pathnames.
+   On Windows the `mdbx_env_openW()`, ``mdbx_env_get_pathW()`()`, `mdbx_env_copyW()`, `mdbx_env_open_for_recoveryW()` are available for now,
+   but the `mdbx_env_get_path()` has been replaced in favor of `mdbx_env_get_pathW()`.
  - Added explicit error message for Buildroot's Microblaze toolchain maintainers.
+ - Added `MDBX_MANAGE_BUILD_FLAGS` build options for CMake.
+ - Speed-up internal `bsearch`/`lower_bound` implementation using branchless tactic, including workaround for CLANG x86 optimiser bug.
+ - A lot internal refinement and micro-optimisations.
+ - Internally counted volume of dirty pages (unused for now but for coming features).
 
 Fixes:
 
  - Never use modern `__cxa_thread_atexit()` on Apple's OSes.
- - Use `MultiByteToWideChar(CP_THREAD_ACP)` instead of `mbstowcs()`.
  - Don't check owner for finished transactions.
  - Fixed typo in `MDBX_EINVAL` which breaks MingGW builds with CLANG.
 
-Minors:
-
- - Fixed variable name typo.
- - Using `ldd` to check used dso.
- - Added `MDBX_WEAK_IMPORT_ATTRIBUTE` macro.
- - Use current transaction geometry for untouched parameters when `env_set_geometry()` called within a write transaction.
- - Minor clarified `iov_page()` failure case.
 
 ## v0.12.0 at 2022-06-19
 

src/man1/mdbx_chk.1

@@ -1,6 +1,6 @@
 .\" Copyright 2015-2022 Leonid Yuriev <leo@yuriev.ru>.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_CHK 1 "2022-06-19" "MDBX 0.12.0"
+.TH MDBX_CHK 1 "2022-08-24" "MDBX 0.12.1"
 .SH NAME
 mdbx_chk \- MDBX checking tool
 .SH SYNOPSIS

src/man1/mdbx_copy.1

@@ -2,7 +2,7 @@
 .\" Copyright 2012-2015 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copyright 2015,2016 Peter-Service R&D LLC <http://billing.ru/>.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_COPY 1 "2022-06-19" "MDBX 0.12.0"
+.TH MDBX_COPY 1 "2022-08-24" "MDBX 0.12.1"
 .SH NAME
 mdbx_copy \- MDBX environment copy tool
 .SH SYNOPSIS

src/man1/mdbx_drop.1

@@ -1,7 +1,7 @@
 .\" Copyright 2021-2022 Leonid Yuriev <leo@yuriev.ru>.
 .\" Copyright 2014-2021 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_DROP 1 "2022-06-19" "MDBX 0.12.0"
+.TH MDBX_DROP 1 "2022-08-24" "MDBX 0.12.1"
 .SH NAME
 mdbx_drop \- MDBX database delete tool
 .SH SYNOPSIS

src/man1/mdbx_dump.1

@@ -2,7 +2,7 @@
 .\" Copyright 2014-2015 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copyright 2015,2016 Peter-Service R&D LLC <http://billing.ru/>.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_DUMP 1 "2022-06-19" "MDBX 0.12.0"
+.TH MDBX_DUMP 1 "2022-08-24" "MDBX 0.12.1"
 .SH NAME
 mdbx_dump \- MDBX environment export tool
 .SH SYNOPSIS

src/man1/mdbx_load.1

@@ -2,7 +2,7 @@
 .\" Copyright 2014-2015 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copyright 2015,2016 Peter-Service R&D LLC <http://billing.ru/>.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_LOAD 1 "2022-06-19" "MDBX 0.12.0"
+.TH MDBX_LOAD 1 "2022-08-24" "MDBX 0.12.1"
 .SH NAME
 mdbx_load \- MDBX environment import tool
 .SH SYNOPSIS

src/man1/mdbx_stat.1

@@ -2,7 +2,7 @@
 .\" Copyright 2012-2015 Howard Chu, Symas Corp. All Rights Reserved.
 .\" Copyright 2015,2016 Peter-Service R&D LLC <http://billing.ru/>.
 .\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
-.TH MDBX_STAT 1 "2022-06-19" "MDBX 0.12.0"
+.TH MDBX_STAT 1 "2022-08-24" "MDBX 0.12.1"
 .SH NAME
 mdbx_stat \- MDBX environment status tool
 .SH SYNOPSIS