selftests/bpf: Fix LDLIBS order

Order of $(LDLIBS) matters to linker, so put it after all the .o and .a
files.

Fixes: 74b5a596 ("selftests/bpf: Replace test_progs and test_maps w/ general rule")
Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191023153128.3486140-1-andriin@fb.com

tools/testing/selftests/bpf/Makefile

@@ -231,14 +231,14 @@ $(TRUNNER_TEST_OBJS): $(TRUNNER_OUTPUT)/%.test.o:			\
 		      $(TRUNNER_EXTRA_HDRS)				\
 		      $(TRUNNER_BPF_OBJS)				\
 		      $$(BPFOBJ) | $(TRUNNER_OUTPUT)
-	cd $$(@D) && $$(CC) $$(CFLAGS) $$(LDLIBS) -c $(CURDIR)/$$< -o $$(@F)
+	cd $$(@D) && $$(CC) $$(CFLAGS) -c $(CURDIR)/$$< $$(LDLIBS) -o $$(@F)
 
 $(TRUNNER_EXTRA_OBJS): $(TRUNNER_OUTPUT)/%.o:				\
 		       %.c						\
 		       $(TRUNNER_EXTRA_HDRS)				\
 		       $(TRUNNER_TESTS_HDR)				\
 		       $$(BPFOBJ) | $(TRUNNER_OUTPUT)
-	$$(CC) $$(CFLAGS) $$(LDLIBS) -c $$< -o $$@
+	$$(CC) $$(CFLAGS) -c $$< $$(LDLIBS) -o $$@
 
 $(TRUNNER_BINARY)-extras: $(TRUNNER_EXTRA_FILES) | $(TRUNNER_OUTPUT)
 ifneq ($2,)
@@ -249,7 +249,7 @@ endif
 $(OUTPUT)/$(TRUNNER_BINARY): $(TRUNNER_TEST_OBJS)			\
 			     $(TRUNNER_EXTRA_OBJS) $$(BPFOBJ)		\
 			     | $(TRUNNER_BINARY)-extras
-	$$(CC) $$(CFLAGS) $$(LDLIBS) $$(filter %.a %.o,$$^) -o $$@
+	$$(CC) $$(CFLAGS) $$(filter %.a %.o,$$^) $$(LDLIBS) -o $$@
 
 endef
 
@@ -303,7 +303,7 @@ verifier/tests.h: verifier/*.c
 		  echo '#endif' \
 		) > verifier/tests.h)
 $(OUTPUT)/test_verifier: test_verifier.c verifier/tests.h $(BPFOBJ) | $(OUTPUT)
-	$(CC) $(CFLAGS) $(LDLIBS) $(filter %.a %.o %.c,$^) -o $@
+	$(CC) $(CFLAGS) $(filter %.a %.o %.c,$^) $(LDLIBS) -o $@
 
 EXTRA_CLEAN := $(TEST_CUSTOM_PROGS)					\
 	prog_tests/tests.h map_tests/tests.h verifier/tests.h		\