2020 Changelog

- Fix TSan report in `system.stack_trace`. [#9832](https://github.com/ClickHouse/ClickHouse/pull/9832) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Removed dependency on `clock_getres`. [#9833](https://github.com/ClickHouse/ClickHouse/pull/9833) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Added identifier names check with clang-tidy. [#9799](https://github.com/ClickHouse/ClickHouse/pull/9799) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Update "builder" docker image. This image is not used in CI but is useful for developers. [#9809](https://github.com/ClickHouse/ClickHouse/pull/9809) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Remove old `performance-test` tool that is no longer used in CI. `clickhouse-performance-test` is great but now we are using way superior tool that is doing comparison testing with sophisticated statistical formulas to achieve confident results regardless to various changes in environment. [#9796](https://github.com/ClickHouse/ClickHouse/pull/9796) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Added most of clang-static-analyzer checks. [#9765](https://github.com/ClickHouse/ClickHouse/pull/9765) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Update Poco to 1.9.3 in preparation for MongoDB URI support. [#6892](https://github.com/ClickHouse/ClickHouse/pull/6892) ([Alexander Kuzmenkov](https://github.com/akuzm))
- Fix build with `-DUSE_STATIC_LIBRARIES=0 -DENABLE_JEMALLOC=0` [#9651](https://github.com/ClickHouse/ClickHouse/pull/9651) ([Artem Zuikov](https://github.com/4ertus2))
- For change log script, if merge commit was cherry-picked to release branch, take PR name from commit description. [#9708](https://github.com/ClickHouse/ClickHouse/pull/9708) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
- Support `vX.X-conflicts` tag in backport script. [#9705](https://github.com/ClickHouse/ClickHouse/pull/9705) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
- Fix `auto-label` for backporting script. [#9685](https://github.com/ClickHouse/ClickHouse/pull/9685) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
- Use libc++ in Darwin cross-build to make it consistent with native build. [#9665](https://github.com/ClickHouse/ClickHouse/pull/9665) ([Hui Wang](https://github.com/huiwang))
- Fix flacky test `01017_uniqCombined_memory_usage`. Continuation of [#7236](https://github.com/ClickHouse/ClickHouse/issues/7236). [#9667](https://github.com/ClickHouse/ClickHouse/pull/9667) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Fix build for native macOS Clang compiler [#9649](https://github.com/ClickHouse/ClickHouse/pull/9649) ([Ivan](https://github.com/abyss7))
- Allow to add various glitches around `pthread_mutex_lock`, `pthread_mutex_unlock` functions. [#9635](https://github.com/ClickHouse/ClickHouse/pull/9635) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Add support for `clang-tidy` in `packager` script. [#9625](https://github.com/ClickHouse/ClickHouse/pull/9625) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Add ability to use unbundled msgpack. [#10168](https://github.com/ClickHouse/ClickHouse/pull/10168) ([Azat Khuzhin](https://github.com/azat))