[PATCH] selftests: netfilter: fix a build error on openSUSE

[PATCH] selftests: netfilter: fix a build error on openSUSE

[Geliang Tang]

This patch fixed the following build error on openSUSE Leap 15.3:

=======================================================================
 gcc     nf-queue.c -lmnl -o tools/testing/selftests/netfilter/nf-queue
 nf-queue.c:13:10: fatal error: libmnl/libmnl.h: No such file or directory
  #include <libmnl/libmnl.h>
           ^~~~~~~~~~~~~~~~~
 compilation terminated.
=======================================================================

It is because libmnl.h is put in the directory of
"/usr/include/libmnl/libmnl/" on openSUSE, not "/usr/include/libmnl/":

 > rpm -ql libmnl-devel
 /usr/include/libmnl
 /usr/include/libmnl/libmnl
 /usr/include/libmnl/libmnl/libmnl.h
 /usr/lib64/libmnl.so
 /usr/lib64/pkgconfig/libmnl.pc

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 tools/testing/selftests/netfilter/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/netfilter/Makefile b/tools/testing/selftests/netfilter/Makefile
index e4f845dd942b..12a4bd689418 100644
--- a/tools/testing/selftests/netfilter/Makefile
+++ b/tools/testing/selftests/netfilter/Makefile
@@ -8,6 +8,7 @@ TEST_PROGS := nft_trans_stress.sh nft_fib.sh nft_nat.sh bridge_brouter.sh \
 	ipip-conntrack-mtu.sh conntrack_tcp_unreplied.sh \
 	conntrack_vrf.sh nft_synproxy.sh
 
+CFLAGS += -I/usr/include/libmnl
 LDLIBS = -lmnl
 TEST_GEN_FILES =  nf-queue
 
-- 
2.34.1