selftests: forwarding: use KHDR_INCLUDES in CFLAGS

KHDR_INCLUDES is typically used to include headers from the kernel
source directory instead of only relying on the ones from the host: they
can be missing or outdated.

The kselftest doc recommends assigning KHDR_INCLUDES to CFLAGS in a
target Makefile. lib.mk will set KHDR_INCLUDES to "-isystem
$(top_srcdir)/usr/include" if the user didn't set it, e.g. if the kernel
was built in a different build directory.

Other net targets have KHDR_INCLUDES added to their CFLAGS.

Link: https://docs.kernel.org/dev-tools/kselftest.html#contributing-new-tests-details
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Ilya Maximets <i.maximets@ovn.org>
Link: https://patch.msgid.link/20260904-net-sft-nf-khdr_includes-v1-2-92455af428e9@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Matthieu Baerts (NGI0) 2026-09-04 18:13:03 +02:00 • committed by Jakub Kicinski
commit f1f4394a8b