Stop the unit tests from running twice

Move the libtest code into a 'libtest' subdirectory and make it
one of the SUBDIRS in the tests Makefile. having it at the top level
required having "." as one of the subdirs, and that caused the
unit tests to be executed twice.

(cherry picked from commit 568f65cc56)

Makefile.tests

@@ -18,6 +18,6 @@ AM_CPPFLAGS +=					\
 	-DNAMED_PLUGINDIR=\"$(pkglibdir)\"	\
 	-DTESTS_DIR=\"$(abs_srcdir)\"
 
-LDADD +=					\
-	$(top_builddir)/tests/libtest.la		\
+LDADD +=						\
+	$(top_builddir)/tests/libtest/libtest.la	\
 	$(CMOCKA_LIBS)

configure.ac

@@ -1581,7 +1581,8 @@ AC_CONFIG_FILES([tests/Makefile
 		 tests/dns/Makefile
 		 tests/ns/Makefile
 		 tests/irs/Makefile
-		 tests/isccfg/Makefile])
+		 tests/isccfg/Makefile
+		 tests/libtest/Makefile])
 
 AC_CONFIG_FILES([tests/unit-test-driver.sh],
 		[chmod +x tests/unit-test-driver.sh])

tests/Makefile.am

@@ -12,19 +12,5 @@ LDADD +=			\
 	$(LIBDNS_LIBS)		\
 	$(LIBNS_LIBS)
 
-SUBDIRS = . isc dns ns isccfg irs
-
-check_LTLIBRARIES = libtest.la
-
-noinst_libtest_ladir = .
-noinst_libtest_la_HEADERS =		\
-	include/tests/dns.h		\
-	include/tests/isc.h		\
-	include/tests/ns.h
-libtest_la_SOURCES =			\
-	$(noinst_libtest_la_HEADERS)	\
-	dns.c				\
-	isc.c				\
-	ns.c
-
-include $(top_srcdir)/Makefile.tests
+SUBDIRS = libtest isc dns ns isccfg irs
+check_PROGRAMS =

tests/libtest/Makefile.am

@@ -0,0 +1,28 @@
+include $(top_srcdir)/Makefile.top
+
+AM_CPPFLAGS +=			\
+	$(LIBISC_CFLAGS)	\
+	$(LIBDNS_CFLAGS)	\
+	$(LIBNS_CFLAGS)		\
+	$(LIBUV_CFLAGS)		\
+	-I$(top_srcdir)/lib/isc
+
+LDADD +=			\
+	$(LIBISC_LIBS)		\
+	$(LIBDNS_LIBS)		\
+	$(LIBNS_LIBS)
+
+check_LTLIBRARIES = libtest.la
+
+noinst_libtest_ladir = ..
+noinst_libtest_la_HEADERS =		\
+	../include/tests/dns.h		\
+	../include/tests/isc.h		\
+	../include/tests/ns.h
+libtest_la_SOURCES =			\
+	$(noinst_libtest_la_HEADERS)	\
+	dns.c				\
+	isc.c				\
+	ns.c
+
+include $(top_srcdir)/Makefile.tests