Externals Update, master branch (2019.01.22.)

This is to update to atlasexternals-2.0.21.

The full list of changes wrt. 2.0.20 is technically a lot (atlasexternals@2.0.20...2.0.21), though conceptually it's a relatively short list.

• Introduced fixes for AnalysisBaseExternals on Ubuntu and macOS. This was cherry picked from 1.0, where I'm trying to revive the analysis release builds for these platforms.
• Added FindCURL.cmake to AtlasLCG to be able to use CURL from the LCG releases if necessary. This I made for ATLINFR-2820 originally, but in the end !20440 (merged) did make this update unnecessary. Still, it's not a bad update per se.
• Updated the code handling Doxygen to work successfully with LCG_94. This is to address ATLINFR-2883.
• Added a lot of CMake changes to make the code work smoothly with CMake >=3.13. (atlasexternals!418 (merged))

It's the last point which is truly non-trivial. I made a lot of changes in the central code to resolve some long standing issues. This required changing a variable naming convention (telling FindFoo.cmake where to look for Foo using FOO_ROOT) that I used in that code since the very beginning. This also means that to incorporate this update in the externals, I also had to update a number of files in this repository. These changes are in all cases very trivial. Though quite numerous...

I've been testing these changes for about a week now, still, since they are significant, it's not impossible that I may have missed something. Let's see what the CI tells us...

This merge request affects 6 packages:

• External/Pythia8
• Projects/AnalysisBase
• Projects/AnalysisTop
• Projects/AthDataQuality
• Projects/AthSimulation
• Projects/Athena

Adding @jchapman ,@vpascuzz as watchers

added Build Externals master review-pending-level-1 labels

CI Result SUCCESS

	Athena	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available at NICOS MR-20525-2019-01-22-22-01
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST 32547] (for remote access see the FAQ for MR reviewers)

The changes look fine and there are no CI issues. Approving.

Cheers,

Jason (L1 shifter)

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 5c295be3

added sweep:ignore label

Hi @akraszna,
when trying to build some packages depending on tdaq-common from a sparse checkout using r23, CMake fails to find tdaq-common. It works with r22, so I suppose it's due to this MR. Could you cross-check if the variables are set correctly?

Thanks,
Rafal

Crap. I think I know what's going on. I probably forgot to update one thing...

mentioned in merge request !20604 (merged)

mentioned in merge request !20632 (merged)