diff --git a/config.mk b/config.mk
index 4f7d4e77..09beb8a0 100644
--- a/config.mk
+++ b/config.mk
@@ -155,10 +155,10 @@ LIB_CXXFLAGS:=$(CXXFLAGS)
 LIB_LDFLAGS:=$(LDFLAGS)
 LIB_LIBADD:=$(LIBADD)
 
-BROKER_CPPFLAGS:=$(LIB_CPPFLAGS) -I../lib
+BROKER_CPPFLAGS:=$(LIB_CPPFLAGS) -I../lib -I/usr/include/cjson -I/usr/local/include/cjson
 BROKER_CFLAGS:=${CFLAGS} -DVERSION="\"${VERSION}\"" -DWITH_BROKER
 BROKER_LDFLAGS:=${LDFLAGS}
-BROKER_LDADD:=
+BROKER_LDADD:=-lcjson
 
 CLIENT_CPPFLAGS:=$(CPPFLAGS) -I.. -I../include
 CLIENT_CFLAGS:=${CFLAGS} -DVERSION="\"${VERSION}\""
@@ -167,6 +167,8 @@ CLIENT_LDADD:=
 
 PASSWD_LDADD:=
 
+PLUGIN_CPPFLAGS:=$(CPPFLAGS) -I../.. -I../../include
+
 ifneq ($(or $(findstring $(UNAME),FreeBSD), $(findstring $(UNAME),OpenBSD), $(findstring $(UNAME),NetBSD)),)
 	BROKER_LDADD:=$(BROKER_LDADD) -lm
 	SEDINPLACE:=-i ""
@@ -339,6 +341,8 @@ endif
 ifeq ($(WITH_COVERAGE),yes)
 	BROKER_CFLAGS:=$(BROKER_CFLAGS) -coverage
 	BROKER_LDFLAGS:=$(BROKER_LDFLAGS) -coverage
+	PLUGIN_CFLAGS:=$(PLUGIN_CFLAGS) -coverage
+	PLUGIN_LDFLAGS:=$(PLUGIN_LDFLAGS) -coverage
 	LIB_CFLAGS:=$(LIB_CFLAGS) -coverage
 	LIB_LDFLAGS:=$(LIB_LDFLAGS) -coverage
 	CLIENT_CFLAGS:=$(CLIENT_CFLAGS) -coverage
diff --git a/plugins/message-timestamp/Makefile b/plugins/message-timestamp/Makefile
index f7383c4f..d8a06ff6 100644
--- a/plugins/message-timestamp/Makefile
+++ b/plugins/message-timestamp/Makefile
@@ -1,3 +1,5 @@
+include ../../config.mk
+
 .PHONY : all binary check clean reallyclean test install uninstall
 
 PLUGIN_NAME=mosquitto_message_timestamp
@@ -7,7 +9,7 @@ all : binary
 binary : ${PLUGIN_NAME}.so
 
 ${PLUGIN_NAME}.so : ${PLUGIN_NAME}.c
-	$(CC) -I../../include -fPIC -shared $< -o $@
+	$(CROSS_COMPILE)$(CC) $(PLUGIN_CPPFLAGS) $(PLUGIN_CFLAGS) $(PLUGIN_LDFLAGS) -fPIC -shared $< -o $@
 
 reallyclean : clean
 clean: