Alibuild

This release speeds up builds using remote stores, and includes a few bug fixes and an extra `--no-remote-store` option for `aliBuild build`.

What's Changed
* Treat empty ALIBUILD_* environment vars as unset by TimoWilken in https://github.com/alisw/alibuild/pull/717
* Remove unused argument for extra rsync options by ktf in https://github.com/alisw/alibuild/pull/720
* Speed up rsync remote store by TimoWilken in https://github.com/alisw/alibuild/pull/719
* Prefer remote revisions to existing local revisions by TimoWilken in https://github.com/alisw/alibuild/pull/718
* Don't clone git repo if we're using a prebuilt tarball by TimoWilken in https://github.com/alisw/alibuild/pull/711
* Make doBuild's return type more sane by TimoWilken in https://github.com/alisw/alibuild/pull/680
* Allow disabling the remote store completely by TimoWilken in https://github.com/alisw/alibuild/pull/722
* Get alibuild version directly, instead of calling pip by TimoWilken in https://github.com/alisw/alibuild/pull/724
* Auto-publish releases to Homebrew by TimoWilken in https://github.com/alisw/alibuild/pull/725


**Full Changelog**: https://github.com/alisw/alibuild/compare/v1.9.1...v1.9.2

What's Changed
* Prefer remote revisions to existing local revisions by TimoWilken in https://github.com/alisw/alibuild/pull/718
* Don't clone git repo if we're using a prebuilt tarball by TimoWilken in https://github.com/alisw/alibuild/pull/711
* Make doBuild's return type more sane by TimoWilken in https://github.com/alisw/alibuild/pull/680


**Full Changelog**: https://github.com/alisw/alibuild/compare/v1.9.1...v1.9.2.rc2

What's Changed
* Treat empty `ALIBUILD_*` environment vars as unset by TimoWilken in https://github.com/alisw/alibuild/pull/717
* Remove unused argument for extra rsync options by ktf in https://github.com/alisw/alibuild/pull/720
* Speed up rsync remote store by TimoWilken in https://github.com/alisw/alibuild/pull/719


**Full Changelog**: https://github.com/alisw/alibuild/compare/v1.9.1...v1.9.2.rc1

This release uses precompiled tarballs by default on CentOS 8, without the user having to specify `--remote-store`.

This release contains significant changes and improvements:

- support for reusing more precompiled packages -- now, packages built with a different `tag:` key in alidist are considered for reuse if the tag they were built from points to the same commit as is being built now
- a fix for uploads when using an s3:// remote store
- a fix in checking for pigz and tar support when building inside a Docker container -- now support is checked inside the container

This pre-release contains a fix for uploads when using an `s3://` remote store.