usleep is optionally unavailable with uClibc-ng.

Added PKG_LICENSE_FILES

Added PKG_CPE_ID for proper CVE tracking.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

remove unused patches
Add patch to:
Automatically detect whether Curve25519 is available in NSS for USE_DH31

Signed-off-by: Antony Antony <antony@phenome.org>

enable libunbound, along with dependency

add kmod-crypto-aead kmod-crypto-gcm dependency to support AES GCM

disable libseccomp
  /git/openwrt/build_dir/target-mips_24kc_musl/libreswan-3.27/include/lswseccomp.h:24:10: fatal error: seccomp.h: No such file or directory
  #include <seccomp.h>
          ^~~~~~~~~~~
add missing dependency nspr

add nss-utils dependency to able to import x509 Certificates  to fix the error
 ipsec import west.p12
 /usr/sbin/ipsec: line 239: pk12util: not found
 /usr/sbin/ipsec: line 84: certutil: not found

remove libnss dependency, nss-utils  util will pull it.
remove unused build option KERNELSRC not necesscay since b4b98e2922.

Signed-off-by: Antony Antony <antony@phenome.org>

remove building kernel module, it is not used and is not working with 4.19

rework the ready to use l2tp-ipsec example

Signed-off-by: Lucian Cristian <lucian.cristian@gmail.com>

use the kernel arch for building the modules

Signed-off-by: Lucian Cristian <lucian.cristian@gmail.com>

Libreswan is a free software implementation of the most widely
supported and standardized VPN protocol based on ("IPsec") and
the Internet Key Exchange ("IKE"). These standards are produced
and maintained by the Internet Engineering Task Force ("IETF").

Signed-off-by: Lucian Cristian <lucian.cristian@gmail.com>