lighttpd: mark module configuration files

Signed-off-by: W. Michael Petullo <mike@flyn.org>

net/lighttpd/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=lighttpd
 PKG_VERSION:=1.4.53
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=https://download.lighttpd.net/lighttpd/releases-1.4.x
@@ -174,6 +174,10 @@ define BuildPlugin
     TITLE:=$(2) module
   endef
 
+  define Package/lighttpd-mod-$(1)/conffiles
+/etc/lighttpd/conf.d/$(4)-$(1).conf
+  endef
+
  ifneq ($(SDK)$(CONFIG_PACKAGE_lighttpd-mod-$(1)),)
   define Package/lighttpd-mod-$(1)/install
 	$(INSTALL_DIR) $$(1)/usr/lib/lighttpd