openmpi redux

[minrk]

retry #140

closes #140

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

I do have some suggestions for making it better though...

For recipe:

• License is not an SPDX identifier (or a custom LicenseRef) nor an SPDX license expression.

Documentation on acceptable licenses can be found here.

[minrk]

Because of #103, this will double build time instead of doubling the size of the build matrix.

found a way in top-level build requirements