Update to rra-c-util 9.1 and C TAP Harness 4.7

Update to rra-c-util 9.1 and C TAP Harness 4.7

Update to rra-c-util 9.1:

* Fix getgroups error handling in k_haspag replacement.
* Check for a working Kerberos header file during configure.
* Use AS_ECHO in all Autoconf macros for better portability.
* Fix reallocarray portability on NetBSD.
* Stop providing a replacement for a broken snprintf.
* Don't check for krb5-config when using explicit paths.
* Fix new warnings with current versions of GCC and Clang.
* Probe for the warning flags supported by the compiler.

Update to C TAP Harness 4.7:

* Report test failures as left and right instead of wanted and seen.
* Fix string comparisons against NULL pointers.
* Honor C_TAP_SOURCE and C_TAP_BUILD along with SOURCE and BUILD.