Provide unit test driver

This adds a unit test driver for BIND with Automake.  It runs the unit
test program provided as its sole command line argument and then looks
for a core dump generated by that test program.  If one is found, the
driver prints the backtrace into the test log.

lib/ns/tests/Makefile.am

@@ -45,3 +45,5 @@ query_test_LDFLAGS =			\
 endif
 
 unit-local: check
+
+LOG_COMPILER = $(builddir)/../../unit-test-driver.sh