vnstat: respect LDFLAGS

net/vnstat/Makefile

@@ -63,7 +63,8 @@ endef
 define Build/Compile/vnstat
 	+$(MAKE) $(PKG_JOBS) -C $(PKG_BUILD_DIR) \
 		$(TARGET_CONFIGURE_OPTS) \
-		CFLAGS="$(TARGET_CFLAGS)"
+		CFLAGS="$(TARGET_CFLAGS)" \
+		LDFLAGS="$(TARGET_LDFLAGS)"
 endef
 
 define Build/Compile/vnstati