easy-soc-libs: more libraries get error flags

Makefile

@@ -17,10 +17,12 @@ objs_lib += ethsw.o
 XXFLAGS += -Wl,-whole-archive -lsw -Wl,-no-whole-archive
 else ifeq ($(PLATFORM),ECONET)
 CFLAGS += -Itest_stub
+LIBETH_CFLAGS += $(DIAG_CFLAGS) -Werror
 objs_lib += econet/econet.o econet/ecnt_prvt.o
 LIBS += -lapi_lib_switchmgr
 else ifeq ($(PLATFORM),TEST)
 CFLAGS += -DIOPSYS_TEST -I/usr/include/libnl3
+LIBETH_CFLAGS += $(DIAG_CFLAGS) -Werror
 objs_lib += test_stub/stub.o
 
 endif