[PATCH] selftests: Fix build when $(O) points to a relative path

[Muhammad Usama Anjum]

Build of bpf and tc-testing selftests fails when the relative path of
the build directory is specified.

make -C tools/testing/selftests O=build0
make[1]: Entering directory '/linux_mainline/tools/testing/selftests/bpf'
../../../scripts/Makefile.include:4: *** O=build0 does not exist.  Stop.
make[1]: Entering directory '/linux_mainline/tools/testing/selftests/tc-testing'
../../../scripts/Makefile.include:4: *** O=build0 does not exist.  Stop.

The fix is same as mentioned in commit 150a27328b68 ("bpf, preload: Fix
build when $(O) points to a relative path").

Signed-off-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
---
 tools/testing/selftests/Makefile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 4eda7c7c15694..aa0faf132c35a 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -178,6 +178,7 @@ all: khdr
 		BUILD_TARGET=$$BUILD/$$TARGET;			\
 		mkdir $$BUILD_TARGET  -p;			\
 		$(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET	\
+				O=$(abs_objtree)		\
 				$(if $(FORCE_TARGETS),|| exit);	\
 		ret=$$((ret * $$?));				\
 	done; exit $$ret;
@@ -185,7 +186,8 @@ all: khdr
 run_tests: all
 	@for TARGET in $(TARGETS); do \
 		BUILD_TARGET=$$BUILD/$$TARGET;	\
-		$(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET run_tests;\
+		$(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET run_tests \
+				O=$(abs_objtree);		    \
 	done;
 
 hotplug:
-- 
2.30.2