tests: add DejaGNU framework

DejaGNU seems to be the 'standard' GNU test framework (which by itself
doesn't say much), but it seems relatively usable and the "remote
system" capabilities might come in handy for virtualisation-based tests
for kernel interactions or something.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/buildtest.sh b/buildtest.sh
index c9dd323..de638f5 100755
--- a/buildtest.sh
+++ b/buildtest.sh
@@ -85,6 +85,7 @@
 	cd "$bdir"
 	../sdist/configure $args
 	make -j5
+	make check
 	make DESTDIR="$TEMP/inst_$cfg" install
 	cd ..
 done