heirloom-mailx: add license info

[Peter: drop unused IEEE part as suggested by Baruch]
Signed-off-by: Danomi Manchego <danomimanchego123@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/heirloom-mailx/heirloom-mailx.mk

@@ -7,6 +7,8 @@
 HEIRLOOM_MAILX_VERSION = 12.5
 HEIRLOOM_MAILX_SOURCE  = heirloom-mailx_$(HEIRLOOM_MAILX_VERSION).orig.tar.gz
 HEIRLOOM_MAILX_SITE    = http://snapshot.debian.org/archive/debian/20110427T035506Z/pool/main/h/heirloom-mailx
+HEIRLOOM_MAILX_LICENSE = BSD-4c, Bellcore (base64), OpenVision (imap_gssapi), RSA Data Security (md5), Network Working Group (hmac), MPLv1.1 (nss)
+HEIRLOOM_MAILX_LICENSE_FILES = COPYING
 
 ifeq ($(BR2_PACKAGE_OPENSSL),y)
 HEIRLOOM_MAILX_DEPENDENCIES += openssl