enhance GROMACS easyblock to add support for optarch X86-64-V? notation

[ostueker]

Otherwise the easyblock will revert to compiling for the current host architecture (which may be wrong in heterogeneous environments).

[boegel]

@boegelbot please test @ jsc-zen3
CORE_CNT=16
EB_ARGS="GROMACS-2025.2-foss-2025b.eb"

[boegel]

lgtm

[boegelbot]

@boegel: Request for testing this PR well received on jsczen3l1.int.jsc-zen3.fz-juelich.de

PR test command 'if [[ develop != 'develop' ]]; then EB_BRANCH=develop ./easybuild_develop.sh 2> /dev/null 1>&2; EB_PREFIX=/home/boegelbot/easybuild/develop source init_env_easybuild_develop.sh; fi; EB_PR=3981 EB_ARGS="GROMACS-2025.2-foss-2025b.eb" EB_CONTAINER= EB_REPO=easybuild-easyblocks EB_BRANCH=develop /opt/software/slurm/bin/sbatch --job-name test_PR_3981 --ntasks="16" ~/boegelbot/eb_from_pr_upload_jsc-zen3.sh' executed!

• exit code: 0
• output:

Submitted batch job 8846

Test results coming soon (I hope)...

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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).

[boegelbot]

Test report by @boegelbot

Overview of tested easyconfigs (in order)

• SUCCESS GROMACS-2025.2-foss-2025b.eb

Build succeeded for 1 out of 1 (total: 42 mins 35 secs) (1 easyconfigs in total)
jsczen3c2.int.jsc-zen3.fz-juelich.de - Linux Rocky Linux 9.6, x86_64, AMD EPYC-Milan Processor (zen3), Python 3.9.21
See https://gist.github.com/boegelbot/ad2e3275c06fa5c0f62b60dc549ad7d2 for a full test report.