xerces: add license information

Signed-off-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/xerces/xerces.mk

@@ -7,6 +7,8 @@
 XERCES_VERSION = 3.1.1
 XERCES_SOURCE = xerces-c-$(XERCES_VERSION).tar.gz
 XERCES_SITE = http://archive.apache.org/dist/xerces/c/3/sources/
+XERCES_LICENSE = Apache-2.0
+XERCES_LICENSE_FILES = LICENSE
 XERCES_MAKE = $(MAKE1)
 XERCES_INSTALL_STAGING = YES
 XERCES_CONF_OPT = --disable-threads \