diff --git a/tools/testing/selftests/sync/Makefile b/tools/testing/selftests/sync/Makefile
index 43db80b71e80..8e04d0afcbd7 100644
--- a/tools/testing/selftests/sync/Makefile
+++ b/tools/testing/selftests/sync/Makefile
@@ -2,14 +2,16 @@ CFLAGS += -O2 -g -std=gnu89 -pthread -Wall -Wextra
 CFLAGS += -I../../../../usr/include/
 LDFLAGS += -pthread
 
-# lib.mk TEST_CUSTOM_PROGS var is for custome tests that need special
-# build rules. lib.mk will run and install them.
-TEST_CUSTOM_PROGS = sync_test
-
-all: $(TEST_CUSTOM_PROGS)
+.PHONY: all clean
 
 include ../lib.mk
 
+# lib.mk TEST_CUSTOM_PROGS var is for custom tests that need special
+# build rules. lib.mk will run and install them.
+
+TEST_CUSTOM_PROGS := $(OUTPUT)/sync_test
+all: $(TEST_CUSTOM_PROGS)
+
 OBJS = sync_test.o sync.o
 
 TESTS += sync_alloc.o
@@ -20,6 +22,16 @@ TESTS += sync_stress_parallelism.o
 TESTS += sync_stress_consumer.o
 TESTS += sync_stress_merge.o
 
-sync_test: $(OBJS) $(TESTS)
+OBJS := $(patsubst %,$(OUTPUT)/%,$(OBJS))
+TESTS := $(patsubst %,$(OUTPUT)/%,$(TESTS))
 
-EXTRA_CLEAN := sync_test $(OBJS) $(TESTS)
+$(TEST_CUSTOM_PROGS): $(TESTS) $(OBJS)
+	$(CC) -o $(TEST_CUSTOM_PROGS) $(OBJS) $(TESTS) $(CFLAGS) $(LDFLAGS)
+
+$(OBJS): $(OUTPUT)/%.o: %.c
+	$(CC) -c $^ -o $@
+
+$(TESTS): $(OUTPUT)/%.o: %.c
+	$(CC) -c $^ -o $@
+
+EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(OBJS) $(TESTS)