[PATCH iproute2] testsuite: fix build failure

[Andrea Claudi <aclaudi@redhat.com>]

After commit 6c09257f1bf6 ("rtnetlink: add new function
rtnl_echo_talk()") "make check" results in:

$ make check

make -C testsuite
make -C iproute2 configure
make -C testsuite alltests
make -C tools
    CC       generate_nlmsg
/usr/bin/ld: /tmp/cc6YaGBM.o: in function `rtnl_echo_talk':
libnetlink.c:(.text+0x25bd): undefined reference to `new_json_obj'
/usr/bin/ld: libnetlink.c:(.text+0x25c7): undefined reference to `open_json_object'
/usr/bin/ld: libnetlink.c:(.text+0x25e3): undefined reference to `close_json_object'
/usr/bin/ld: libnetlink.c:(.text+0x25e8): undefined reference to `delete_json_obj'
collect2: error: ld returned 1 exit status
make[2]: *** [Makefile:6: generate_nlmsg] Error 1
make[1]: *** [Makefile:40: generate_nlmsg] Error 2
make: *** [Makefile:130: check] Error 2

This is due to json function calls included in libutil and not in
libnetlink. Fix this adding libutil.a to the tools Makefile, and linking
against libcap as required by libutil itself.

Fixes: 6c09257f1bf6 ("rtnetlink: add new function rtnl_echo_talk()")
Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
---
 testsuite/tools/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/testsuite/tools/Makefile b/testsuite/tools/Makefile
index e3e771d7..e0162ccc 100644
--- a/testsuite/tools/Makefile
+++ b/testsuite/tools/Makefile
@@ -2,8 +2,8 @@
 CFLAGS=
 include ../../config.mk
 
-generate_nlmsg: generate_nlmsg.c ../../lib/libnetlink.c
-	$(QUIET_CC)$(CC) $(CPPFLAGS) $(CFLAGS) $(EXTRA_CFLAGS) -I../../include -I../../include/uapi -include../../include/uapi/linux/netlink.h -o $@ $^ -lmnl
+generate_nlmsg: generate_nlmsg.c ../../lib/libnetlink.a ../../lib/libutil.a
+	$(QUIET_CC)$(CC) $(CPPFLAGS) $(CFLAGS) $(EXTRA_CFLAGS) -I../../include -I../../include/uapi -include../../include/uapi/linux/netlink.h -o $@ $^ -lmnl -lcap
 
 clean:
 	rm -f generate_nlmsg
-- 
2.37.3