The patch is needed, because if you have mkl installed in /opt or a standard location, mkl will be chosen above OpenBLAS.

@tstrempel is this patch needed for the more recent versions as well?
Armadillo-9.700.2-foss-2019a.eb, Armadillo-9.880.1-foss-2020a.eb

if so, would you mind updating those easyconfigs as well?

@smoors Yes, it is needed. I'll also provide a version for 2019b. I just didn't want to commit the same file 4 times as I didn't know how this would be handeled.
Is it allowed to commit multiple EasyConfigs in one pull request?

Is it allowed to commit multiple EasyConfigs in one pull request?

yes, you can upload multiple easyconfigs in one PR, although it's a good idea to limit the number of easyconfigs to max 10 to ease the review process.

@tstrempel protip: it looks like you are manually updating the checksums?
that's not needed, you can let EB do it for you:

eb --inject-checksums --force Armadillo-9.880.1-foss-2020a.eb

Test report by @smoors
SUCCESS
Build succeeded for 8 out of 8 (4 easyconfigs in this PR)
node358.hydra.os - Linux centos linux 7.7.1908, x86_64, Intel(R) Xeon(R) Gold 6148 CPU @ 2.40GHz (skylake_avx512), Python 2.7.5
See https://gist.github.com/d6e185c32515dec8aa7ba1e3ee98e7f1 for a full test report.

Going in, thanks @tstrempel!