improve lib dependencies

Makefile

@@ -1,8 +1,8 @@
 include config.mk
 
 CFLAGS	+= -Wall -DNS_ENABLE_IPV6
-LIBS	= $(MORELIBS) -lm
-LIBS 	+= -lcurl -lconfig
+LIBS	= $(MORELIBS)
+LIBS 	+= -lcurl
 
 TARGETS=
 OTR_OBJS = json.o \
@@ -20,7 +20,12 @@ OTR_EXTRA_OBJS =
 
 CFLAGS += -DGHASHPREC=$(GHASHPREC)
 
-LIBS += -llmdb
+CFLAGS += $(LMDB_CFLAGS)
+LIBS += $(LMDB_LIBS)
+
+CFLAGS += $(LIBCONFIG_CFLAGS)
+LIBS += $(LIBCONFIG_LIBS)
+
 LIBS += -lpthread
 
 define CPP_CONDITION
@@ -31,10 +36,13 @@ true \n
 #endif' | $(CPP) -P - >/dev/null 2>&1 && echo yes
 endef
 
+LIBLM ?= no
+
 ifeq ($(WITH_MQTT),yes)
 	CFLAGS += -DWITH_MQTT=1
 	CFLAGS += $(MOSQUITTO_CFLAGS)
-	LIBS += $(MOSQUITTO_LIBS) -lm
+	LIBS += $(MOSQUITTO_LIBS)
+	LIBLM ?= yes
 endif
 
 ifeq ($(WITH_PING),yes)
@@ -45,6 +53,8 @@ ifeq ($(WITH_LUA),yes)
 	CFLAGS += -DWITH_LUA=1 $(LUA_CFLAGS)
 	LIBS   += $(LUA_LIBS)
 	OTR_OBJS += hooks.o
+else
+	LIBLM ?= yes
 endif
 
 ifeq ($(WITH_ENCRYPT),yes)
@@ -79,6 +89,10 @@ ifeq ($(WITH_TZ),yes)
 	OCAT_EXTRA_OBJS += zonedetect.o
 endif
 
+ifeq ($(LIBLM),yes)
+	LIBS += -lm
+endif
+
 ifeq ($(JSON_INDENT),yes)
 	CFLAGS += -DJSON_INDENT="\" \""
 else

config.mk.in

@@ -116,3 +116,9 @@ LUA_LIBS   = `$(PKG_CONFIG) --libs lua`
 
 SODIUM_CFLAGS = `$(PKG_CONFIG) --cflags libsodium`
 SODIUM_LIBS   = `$(PKG_CONFIG) --libs libsodium`
+
+LMDB_CFLAGS = `$(PKG_CONFIG) --cflags lmdb`
+LMDB_LIBS   = `$(PKG_CONFIG) --libs lmdb`
+
+LIBCONFIG_CFLAGS = `$(PKG_CONFIG) --cflags libconfig`
+LIBCONFIG_LIBS   = `$(PKG_CONFIG) --libs libconfig`