diffutils: define license

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/diffutils/diffutils.mk

@@ -7,6 +7,8 @@
 DIFFUTILS_VERSION = 3.2
 DIFFUTILS_SITE = $(BR2_GNU_MIRROR)/diffutils
 DIFFUTILS_DEPENDENCIES = $(if $(BR2_NEEDS_GETTEXT_IF_LOCALE),gettext)
+DIFFUTILS_LICENSE = GPLv3+
+DIFFUTILS_LICENSE_FILES = COPYING
 
 ifeq ($(BR2_PACKAGE_BUSYBOX),y)
 DIFFUTILS_DEPENDENCIES += busybox