libxslt: add patches copied from Debian to fix CVEs

- there are multiple open CVEs, this adds patches for them
- adds --disable-silent-rules for verbose build output

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>

libs/libxslt/Makefile

@@ -1,5 +1,5 @@
 #
-# Copyright (C) 2014 OpenWrt.org
+# Copyright (C) 2014 - 2018 OpenWrt.org
 #
 # This is free software, licensed under the GNU General Public License v2.
 # See /LICENSE for more information.
@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libxslt
 PKG_VERSION:=1.1.28
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:= \
@@ -64,6 +64,7 @@ define Package/xsltproc/description
 endef
 
 CONFIGURE_ARGS+= \
+	--disable-silent-rules \
 	--enable-shared \
 	--enable-static \
 	--without-python \