lighttpd: Add missing 'server.modules' in some config files

e.g. 20-auth.conf

Signed-off-by: David Yang <mmyangfl@gmail.com>

net/lighttpd/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=lighttpd
 PKG_VERSION:=1.4.49
-PKG_RELEASE:=4
+PKG_RELEASE:=5
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=https://download.lighttpd.net/lighttpd/releases-1.4.x
@@ -180,6 +180,10 @@ define BuildPlugin
 	$(INSTALL_DIR) $$(1)/etc/lighttpd/conf.d
 	if [ -f $(PKG_BUILD_DIR)/doc/config/conf.d/$(1).conf ]; then \
 		$(CP) $(PKG_BUILD_DIR)/doc/config/conf.d/$(1).conf $$(1)/etc/lighttpd/conf.d/$(4)-$(1).conf ; \
+		if ! grep -qF 'mod_$(1)' $$(1)/etc/lighttpd/conf.d/$(4)-$(1).conf; then \
+			sed -i "`sed '/^##/ !q' $$(1)/etc/lighttpd/conf.d/$(4)-$(1).conf | wc -l` i\
+server.modules += ( \"mod_$(1)\" )" $$(1)/etc/lighttpd/conf.d/$(4)-$(1).conf ; \
+		fi \
 	else \
 		echo 'server.modules += ( "mod_$(1)" )' > $$(1)/etc/lighttpd/conf.d/$(4)-$(1).conf ; \
 	fi