--- Makefile.orig	2021-09-03 20:08:25 UTC
+++ Makefile
@@ -114,7 +114,7 @@ ifneq ($(cjson-pass)$(system-cjson-pass),)
   JSON2CBOR_SOURCES = tools/json2cbor/json2cbor.c
   INSTALL_TARGETS += $(bindir)/json2cbor
   ifeq ($(system-cjson-pass),1)
-    LDFLAGS_CJSON = -lcjson
+    LDFLAGS_CJSON = -I$(LOCALBASE)/include -L$(LOCALBASE)/lib -lcjson
   else
     JSON2CBOR_SOURCES += src/cjson/cJSON.c
     json2cbor_CCFLAGS = -I$(SRCDIR)src/cjson
@@ -238,7 +238,6 @@ tag: distcheck
 cflags := $(CPPFLAGS) -I$(SRCDIR)src
 cflags += -std=gnu99 $(CFLAGS) \
 	-Werror=incompatible-pointer-types \
-	-Werror=implicit-function-declaration \
 	-Werror=int-conversion
 %.o: %.c
 	@test -d $(@D) || $(MKDIR) $(@D)