Update to rra-c-util 8.2 and C TAP Harness 4.7

Update to rra-c-util 8.2 and C TAP Harness 4.7

Update to rra-c-util 8.2:

* Implement explicit_bzero with memset if it is not available.
* Reformat all C source using clang-format 10.
* Work around Test::Strict not skipping .git directories.
* Fix warnings with perltidy 20190601 and Perl::Critic 1.134.
* Improve check for obsolete strings.
* Use a more standard all-permissive license.
* Add SPDX-License-Identifier headers to all substantial source files.
* Skip more build system files when running the test suite.
* Fix warnings with Clang 10, GCC 10, and the Clang static analyzer.
* Exclude more valgrind false positives with Kerberos libraries.

Update to C TAP Harness 4.7:

* Fix warnings with GCC 10.
* Reformat all C source using clang-format 10.
* Fixed malloc error checking in bstrndup.
* Add support for valgrind testing via test list options.
* Report test failures as left and right, not wanted and seen.
* Fix is_string comparisons involving NULL pointers and "(null)".
* Add SPDX-License-Identifier headers to all substantial source files.