[PATCH v1] selftests: Use optional USERCFLAGS and USERLDFLAGS

["Mickaël Salaün" <mic@digikod.net>]

This change enables to extend CFLAGS and LDFLAGS from command line, e.g.
to extend compiler checks: make USERCFLAGS=-Werror USERLDFLAGS=-static

USERCFLAGS and USERLDFLAGS are documented in
Documentation/kbuild/makefiles.rst and Documentation/kbuild/kbuild.rst

This should be backported (down to 5.10) to improve previous kernel
versions testing as well.

Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220909103901.1503436-1-mic@digikod.net
---
 tools/testing/selftests/lib.mk | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index d44c72b3abe3..da47a0257165 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -119,6 +119,11 @@ endef
 clean:
 	$(CLEAN)
 
+# Enables to extend CFLAGS and LDFLAGS from command line, e.g.
+# make USERCFLAGS=-Werror USERLDFLAGS=-static
+CFLAGS += $(USERCFLAGS)
+LDFLAGS += $(USERLDFLAGS)
+
 # When make O= with kselftest target from main level
 # the following aren't defined.
 #

base-commit: 7e18e42e4b280c85b76967a9106a13ca61c16179
-- 
2.37.2