Update S2 to use external Abseil

[paleolimbot]

No description provided.

[codecov-commenter]

Codecov Report

Merging #134 (ba6f4d0) into master (c87c10d) will not change coverage.
The diff coverage is n/a.

❗ Current head ba6f4d0 differs from pull request most recent head 57e9369. Consider uploading reports for the commit 57e9369 to get more accurate results

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##           master     #134   +/-   ##
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  Coverage   94.04%   94.04%           
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  Files          40       40           
  Lines        2987     2987           
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  Hits         2809     2809           
  Misses        178      178           

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[edzer]

@paleolimbot is this ready to go? Final deadline from CRAN is Sep 30.

[paleolimbot]

I was still waiting for literally any action upstream on S2 since it sounded like there may have been hope. Abseil is the "hard" part in the sense that it contains a lot of compiler-specific code that needs some workarounds for CRAN. I did that first and it looks like it will work. If the upstream PR isn't merged I'll probably recreate it by changing the header includes rather than update based on the untested PR.

[edzer]

OK. Shall we plan to merge this & submit by Sep 23, then?

[paleolimbot]

There's no point in merging this yet because it doesn't actually fix the issue...it includes Abseil, which is the "fix", but it doesn't use Abseil (yet). I can devote Monday to this and will make sure we have some checks in motion by then.

[paleolimbot]

I can confirm that this fixes #79 via a Dockerfile based on debian/testing:

FROM cran/debian
RUN apt update && apt install -y gcc-11 g++-11

RUN mkdir ~/.R && echo 'CXX11=g++-11' > ~/.R/Makevars && echo 'CXX=g++-11' >> ~/.R/Makevars && echo 'CC=gcc-11' >> ~/.R/Makevars
RUN echo 'CCFLAGS = -Wall -pedantic -O2' >> ~/.R/Makevars && echo 'CXXFLAGS = -Wall -pedantic -O2' >> ~/.R/Makevars && echo 'CXX11FLAGS = -Wall -pedantic -O2' >> ~/.R/Makevars 

I also checked rhub::check_for_cran() and rhub::check_on_solaris() since a lot of the nuts-and-bolts internal code changed.