mbedtls and libcoap cause a conflict because there are object files which are same name
To fix it I added prefix at object files
CSRCS += uri.c
AOBJS = $(ASRCS:.S=$(OBJEXT))
-COBJS = $(CSRCS:.c=$(OBJEXT))
+COBJS = $(patsubst %.c, libcoap_%$(OBJEXT), $(CSRCS))
SRCS = $(ASRCS) $(CSRCS)
OBJS = $(AOBJS) $(COBJS)
$(AOBJS): %$(OBJEXT): %.S
$(call ASSEMBLE, $<, $@)
-$(COBJS): %$(OBJEXT): %.c
+$(COBJS): libcoap_%$(OBJEXT): %.c
$(call COMPILE, $<, $@)
.built: $(OBJS)