magma: fix __ieee128 is undefined on ppc64le with glibc 2.26

[branfosj]

(created using eb --new-pr)

This is the magma part of #11913. The 2019a version also includes the CUDA SM patch from #11861 (which is added to avoid needing different patches for the 2019a and 2019b versions of magma).

CUDA 11 does not require this fix, so it is not applied to magma in 2020a/b toolchains.

[branfosj]

Test report by @branfosj
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in total)
bear-pg0306u11a.bear.cluster - Linux RHEL 8.2, POWER, 8335-GTX (power9le), Python 3.6.8
See https://gist.github.com/d7ec006c3e43313e7744fad7ef356228 for a full test report.

[branfosj]

Test report by @branfosj
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in total)
bear-pg0212u17a.bear.cluster - Linux centos linux 8.2.2004, x86_64, Intel(R) Xeon(R) CPU E5-2640 v4 @ 2.40GHz (broadwell), Python 3.6.8
See https://gist.github.com/be76970e74957d67bd7fd30bc14bca44 for a full test report.

[boegel]

@boegelbot please test @ generoso
CORE_CNT=16

[boegelbot]

@boegel: Request for testing this PR well received on generoso

PR test command 'EB_PR=11930 EB_ARGS= /apps/slurm/default/bin/sbatch --job-name test_PR_11930 --ntasks="16" ~/boegelbot/eb_from_pr_upload_generoso.sh' executed!

• exit code: 0
• output:

Submitted batch job 12345

Test results coming soon (I hope)...

- notification for comment with ID 751444526 processed

Message to humans: this is just bookkeeping information for me,
it is of no use to you (unless you think I have a bug, which I don't).

[boegel]

lgtm

[boegel]

Test report by @boegel
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in total)
node3307.joltik.os - Linux centos linux 7.9.2009, x86_64, Intel(R) Xeon(R) Gold 6242 CPU @ 2.80GHz (cascadelake), Python 3.6.8
See https://gist.github.com/93d5eea09477f962de237a95a78d114a for a full test report.

[boegel]

Test report by @boegel
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in total)
node3563.doduo.os - Linux RHEL 8.2, x86_64, AMD EPYC 7552 48-Core Processor (zen2), Python 3.6.8
See https://gist.github.com/e5a7c26cb945fb001de2192d5dceb8f9 for a full test report.

[boegel]

Going in, thanks @branfosj!