[RFC PATCH tip 2/2] sched/membarrier selftests: Fix: use KHDR_INCLUDES for kernel headers

[Mathieu Desnoyers]

Use $(KHDR_INCLUDES) as lookup path for kernel headers. This prevents
building against kernel headers from the build environment in scenarios
where kernel headers are installed into a specific output directory
(O=...).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
---
 tools/testing/selftests/membarrier/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/membarrier/Makefile b/tools/testing/selftests/membarrier/Makefile
index 34d1c81a2324..fc840e06ff56 100644
--- a/tools/testing/selftests/membarrier/Makefile
+++ b/tools/testing/selftests/membarrier/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
-CFLAGS += -g -I../../../../usr/include/
+CFLAGS += -g $(KHDR_INCLUDES)
 LDLIBS += -lpthread
 
 TEST_GEN_PROGS := membarrier_test_single_thread \
-- 
2.25.1