Update to rra-c-util 5.10 and C TAP Harness 3.4

Update to rra-c-util 5.10 and C TAP Harness 3.4

Update to rra-c-util 5.10:

* Add missing va_end to xasprintf implementation.
* Fix Perl test suite framework for new Automake relative paths.
* Improve portability to Kerberos included in Solaris 10.
* Use appropriate warning flags with Clang (currently not warning clean).

Update to C TAP Harness 3.4:

* Fix segfault in runtests with an empty test list.
* Display verbose test results with -v or C_TAP_VERBOSE.
* Test infrastructure builds cleanly with Clang warnings.
* Support comments and blank lines in test lists.