Bugfix 2531 compilation errors

[jprestop]

Expected Differences

• Do these changes introduce new tools, command line arguments, or configuration file options? [No]
  
  If yes, please describe:
  

• Do these changes modify the structure of existing or add new output data types (e.g. statistic line types or NetCDF variables)? [No]
  
  If yes, please describe:
  

Pull Request Testing

• Describe testing already performed for these changes:
  
  Compiled on Hera with these changes

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  
  Review and compile on Hera if desired

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [Yes]

• Do these changes include sufficient testing updates? [Yes]

• Will this PR result in changes to the test suite? [I hope not]
  
  If yes, describe the new output and/or changes to the existing output:
  

• Please complete this pull request review by [As soon as possible after the tests pass].
  

Pull Request Checklist

See the METplus Workflow for details.

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• Complete the PR definition above.
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  Select: Reviewer(s)
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  Select: Milestone as the version that will include these changes
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[JohnHalleyGotway]

Adding the -std flag to configure.ac makes me a bit nervous. I worry about whether any of the compilers out there will balk at that option and complain that it's not supported.

[JohnHalleyGotway]

I approve of these changes.

While I worry that adding -std directly to configure.ac has the potential to cause problems with other compilers, I do think we should proceed with this solution.

However, we should call particular attention to this change to see if it breaks the compilation of MET elsewhere during the testing of the beta2 and rc1 development releases.

[jprestop]

Thanks @JohnHalleyGotway. You make good points. I'll start installing these on Monday on various machines. Hopefully, like you said, it won't cause problems elsewhere.