Tag to be used with the master branch of atlas/athena.
Update(s) since 2.0.19:
  - Introduced LCG_IGNORED_SYSTEM_PATHS and LCG_SYSTEM_IGNORE_PATH for influencing globally what directories to ignore during the build and environment setup script generation.
  - Fixed the RPM dependency problem introduced when FindTBB.cmake started setting up TBB_VERSION using tbb/tbb_stddef.h.

Tag to be used with the 21.X branches of atlas/athena.
Updates in this tag:
  - Made AnalysisBaseExternals functional on the PPC64 platform.
  - Added some dictionary improvements for detecting upstream changes more reliably that should trigger a dictionary re-generation. Also made the dictionary generation more reliable on MacOS Mojave.
  - Updated AnalysisBaseExternals and AthAnalysisExternals to LCG_94a. This meant updating the version of ROOT and Davix built for AnalysisBaseExternals.

Tag to be used with the master branch of atlas/athena.
Update(s) since 2.0.18:
  - Updated Acts to allow forcing a clean re-build of the project whenever necessary.
  - Updated the Acts build to propagate additional build configuration settings to the external.

Tag to be used with the master branch of atlas/athena.
Update(s) since 2.0.17:
  - Updated AnalysisBaseExternals to build TBB, and make the standalone version of ROOT build against that version of TBB;
  - Made it possible to build AnalysisBaseExternals on PPC64 and in C++17 mode;
  - Updated Acts to version 0.7.3;
  - Updates to CheckerGccPlugins for GCC 9;
  - Updated all projects to use LCG_94a.

Tag to be used with the master branch of atlas/athena.
Update(s) since 2.0.15:
  - Made the (Reflex) dictionary generation code a bit smarter, to better detect "upstream header changes".

Tag to be used with the master branch of atlas/athena.
Updates since 2.0.15:
  - Updated the CLHEP and G4 builds to properly clean up when switching to a different version of CLHEP/G4. Allowing for CI friendly version updates of these two externals.
  - Updated the ROOT dictionary building CMake code to better detect when Reflex dictionaries need to be re-generated in an incremental build.

Tag to be used with the master branch of atlas/athena.
Updates since 2.0.15:
  - Added FindSuperchic.cmake and updated FindHerwig3.cmake to work with newer Herwig versions;
  - Updated to CLHEP 2.4.0.1;
  - Updated to Geant4 10.4.2.1;
  - Added GeoModel as an external to AthenaExternals and AthSimulationExternals;
  - Added a speedup to calling find_package(LCG ...) in user projects.

Tag to be used with the 21.X branches of atlas/athena.
Updates in this tag:
  - Added FindSuperchic.cmake for finding that new generator (not functional in this release yet);
  - Made FindHerwig3.cmake more robust, and functional with newer Herwig versions;
  - Backported some technical AtlasLCG updates from the master branch.

Tag to be used with the 21.X branches of atlas/athena.
Updates in this tag:
  - Updated the build of Davix to happen on any linux system that should be able to build it. (Changed from only building it on SLC6 and CC7.)
  - Updated the Geant4 version to 10.1.patch03.atlas07.
  - Updated the lwtnn version to 2.8.
  - Suppressed some warnings from new CMake versions.

Tag to be used ONLY WITH NIGHTLY BUILDS of the master branch of atlas/athena.
Updates since 2.0.14:
  - Update gcc checker plugins to avoid some false positives from the
    thread-safety checker and aldo to copy documentation here.
  - Fix ACTS version used in the build.
  - Update lwtnn to 2.8.
  - Minor cmake fixes

Tag to be used ONLY WITH NIGHTLY BUILDS of the master branch of atlas/athena.
Updates since 2.0.13:
  - Added FindFreetype to AtlasLCG/modules, to properly get the Freetype library shipped with LCG, instead of the system one.
    This fixes a runtime error in VP1 (https://its.cern.ch/jira/browse/ATLASVPONE-427)

Tag to be used with the 21.X branches of atlas/athena.
Updates in this tag:
  - Fixed up the CMake version requirements in the code a bit;
  - Added a find-module for the C++ Guidelines Support Library;
  - Fixed the environment setup for matplotlib from LCG_94;
  - Upgraded KLFitter to version 1.2.1;
  - Added fixes for building ROOT 6.14/04 on bare-bones Ubuntu systems.

Tag to be used ONLY WITH NIGHTLY BUILDS of the master branch of atlas/athena.
Updates since 2.0.12:
  - Switched to build projects in c++17 mode by default, except with GCC <7;
  - Added the dependencies of matplotlib to make it usable out of pyanalysis in LCG_94.

Tag to be used with the 21.X branches of atlas/athena.
Updates in this tag:
  - Upgraded to HDF5 version 1.10.3;
  - Added a the CMake version used for the build to the project's ReleaseData file;
  - Upgraded to the (currently) latest version of yampl;
  - Fixed an issue with the build timestamps saved into the ReleaseData file.

Tag to be used ONLY WITH NIGHTLY BUILDS of the master branch of atlas/athena.
Updates since 2.0.11:
  - Revived the "doc" target for Doxygen documentation generation;
  - Updated all "standalone" externals to versions in sync with LCG_94;
  - Upgraded to the (currently) latest version of yampl;
  - Added the build's CMake version to the generated ReleaseData file;
  - Upgraded to HDF5-1.10.3;
  - Patched CLHEP to remove build warnings with GCC 8;
  - Added FindLibXslt.cmake, and made Findtdaq.cmake use it;
  - Added a fix for the build time inconsistency that we had in ReleaseData.

Tag to be used with the 21.X branches of atlas/athena.
Updates in this tag:
  - Updated BAT and KLFitter to re-build when switching from 1.0.38 to this tag. (To account for the ROOT version change.)

Tag to be used with the 21.X branches of atlas/athena.
Updates in this tag:
  - Updated AtlasLCG to be compatible with LCG_94;
  - Upgraded all packages used by AnalysisBaseExternals to have the same version as they do in LCG_94;
  - Upgraded AthAnalysisExternals to build against LCG_94 by default;
  - Fixed a small issue in HDF5's build, where it wouldn't use ZLIB correctly from the LCG release;
  - Backported some technical updates from the master branch;
  - Added the ability to build Doxygen documentation using CMake once again.

Tag to be used ONLY WITH NIGHTLY BUILDS of the master branch of atlas/athena.
Updates since 2.0.10:
  - Upgraded KLFitter to version 1.2.0;
  - Upgraded HDF5 to version 1.10.2, and switched to building it with CMake;
  - Upgraded lwtnn to version 2.7.1;
  - Upgraded all projects to use LCG_94, with the exception of AnalysisBaseExternals (for now).

Tag to be used with the 21.X branches of atlas/athena.
Updates in this tag:
  - Added extra find-modules to make ART's dependencies work from >=LCG_91 versions;
  - Updated HDF5 to 1.10.2, and switched to building it with CMake;
  - Updated KLFitter to v1.2.0;
  - Updated lwtnn to v2.7.1.

Tag to be used ONLY WITH NIGHTLY BUILDS of the master branch of atlas/athena.
Updates since 2.0.9:
  - Updates to AtlasLCG to handle the externals needed by ART correctly in LCG_93+;
  - Taught CheckerGccPlugins about the naming convention introduced in Gaudi's PluginSvc v2.