Rename to _openmp_mutex

[isuruf]

Checklist

• [ ] Used a fork of the feedstock to propose changes
• [ ] Bumped the build number (if the version is unchanged)
• [ ] Reset the build number to 0 (if the version changed)
• [ ] Re-rendered with the latest conda-smithy (Use the phrase code>@<space/conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• [ ] Ensured the license file is being packaged.

Closes #11

[conda-forge-linter]

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

I wanted to let you know that I linted all conda-recipes in your PR (recipe) and found some lint.

Here's what I've got...

For recipe:

• The home item is expected in the about section.
• The license item is expected in the about section.
• The summary item is expected in the about section.
• The outputs section contained an unexpected subsection name. target is not a valid subsection name.
• The outputs section contained an unexpected subsection name. target is not a valid subsection name.
• The outputs section contained an unexpected subsection name. target is not a valid subsection name.
• The outputs section contained an unexpected subsection name. target is not a valid subsection name.

[isuruf]

@beckermr, if you have time, please send a PR to port this over to 9.2.0

[beckermr]

Ready to merge @isuruf?