Specify dependencies libs explicitly.

Such setup is better for cross compilation. Also changed Makefile to
properly make the project with these libraries.

deps/libnfnetlink/utils/iftest.c

@@ -0,0 +1,52 @@
+/* simple test for index to interface name API */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <net/if.h>
+
+#include <libnfnetlink/libnfnetlink.h>
+
+int main(int argc, char *argv[])
+{
+	int idx;
+	struct nlif_handle *h;
+	char name[IFNAMSIZ];
+	unsigned int flags;
+
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s <interface>\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	h = nlif_open();
+	if (h == NULL) {
+		perror("nlif_open");
+		exit(EXIT_FAILURE);
+	}
+
+	if (nlif_query(h) == -1) {
+		fprintf(stderr, "failed query to retrieve interfaces: %s\n",
+			strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	idx = if_nametoindex(argv[1]);
+
+	/* Superfluous: just to make sure nlif_index2name is working fine */
+	if (nlif_index2name(h, idx, name) == -1)
+		fprintf(stderr, "Cannot translate device idx=%u\n", idx);
+
+	if (nlif_get_ifflags(h, idx, &flags) == -1) {
+		fprintf(stderr, "Cannot get flags for device `%s'\n", argv[1]);
+		exit(EXIT_FAILURE);
+	}
+
+	printf("index (%d) is %s (%s) (%s)\n", idx, argv[1],
+		flags & IFF_RUNNING ? "RUNNING" : "NOT RUNNING",
+		flags & IFF_UP ? "UP" : "DOWN");
+
+	nlif_close(h);
+	return EXIT_SUCCESS;
+}