* Probe for Kerberos headers using file checks instead of compiles.
* Improve probe for the Heimdal libroken library.
* Always build with large file support.
* Conditionally call AM_PROG_AR for portability to new Autotools.
Update to C TAP Harness 2.2:
* Allow more easily running single programs under tests/runtests.
* Flush the output from the test harness after each test.