Add build tags for integration tests

Add the necessary build tags and configuration so that integration tests
can properly build against device mapper and btrfs libraries.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

hack/libdm_tag.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+tmpdir="$PWD/tmp.$RANDOM"
+mkdir -p "$tmpdir"
+trap 'rm -fr "$tmpdir"' EXIT
+cc -c -o "$tmpdir"/libdm_tag.o -x c - > /dev/null 2> /dev/null << EOF
+#include <libdevmapper.h>
+int main() {
+	struct dm_task *task;
+	return 0;
+}
+EOF
+if test $? -ne 0 ; then
+	echo libdm_no_deferred_remove
+fi