Update 8.0.3-RC latest versions of utils and Makefiles

This is a PR to collate updates to utils and Makefiles that should go into GS2 8.0.3, but which do not have their own GS2 pull requests. This saves making multiple GS2 PRs just to update the externals. This should not be merged until 8.0.3-RC is ready for release.

The state of the branch 8.0.3-RC+latest-externals is:

• GS2 branch 8.0.3-RC

• utils next

• Makefiles master

This PR contains utils updates:

• bugfix/single-precision-timing (pull request #30)

• feature/write-exit-reason (pull request #32)

• bugfix/guard_against_empty_send_in_redistribute (pull request #31)

• feature/store-verbosity-backwards-compatible (pull request #36)

• feature/update-exit-codes (pull request #33)

• admin/changelog-for-8.0.3 (pull request #38)

• bugfix/add_code_matches_to_exit_code_type (pull request #39)

• micro/update-changelog-8.0.3 (pull request #40)

and Makefiles updates:

• bugfix/marconi-hdf5 (pull request #30)

• bugfix/archer-build_gs2 (pull request #31)

• fedora_makefile_parallelnetcdf_fix (pull request #29)

• 8.0.3-RC (pull request #32)