[strongSwan] unable to load plugin features/unmet dependencies

[Cindy Moore]

I notice this in the syslog:

Dec 10 13:29:53 vpn charon: 00[DMN] Starting IKE charon daemon
(strongSwan 5.2.1, Linux 3.13.0-40-generic, x86_64)
Dec 10 13:29:53 vpn charon: 00[CFG] loading ca certificates from
'/etc/ipsec.d/cacerts'
Dec 10 13:29:53 vpn charon: 00[CFG]   loaded ca certificate "C=US,
O=ThatsUs, CN=strongSwan Root CA" from
'/etc/ipsec.d/cacerts/strongswanCert.pem'
Dec 10 13:29:53 vpn charon: 00[CFG] loading aa certificates from
'/etc/ipsec.d/aacerts'
Dec 10 13:29:53 vpn charon: 00[CFG] loading ocsp signer certificates
from '/etc/ipsec.d/ocspcerts'
Dec 10 13:29:53 vpn charon: 00[CFG] loading attribute certificates
from '/etc/ipsec.d/acerts'
Dec 10 13:29:53 vpn charon: 00[CFG] loading crls from '/etc/ipsec.d/crls'
Dec 10 13:29:53 vpn charon: 00[CFG] loading secrets from '/etc/ipsec.secrets'
Dec 10 13:29:53 vpn charon: 00[CFG]   loaded RSA private key from
'/etc/ipsec.d/private/vpnHostKey.pem'
Dec 10 13:29:53 vpn charon: 00[CFG]   loaded EAP secret for cindy
Dec 10 13:29:53 vpn charon: 00[LIB] loaded plugins: charon aes des rc2
sha1 sha2 md5 random nonce x509 revocation constraints pubkey pkcs1
pkcs7 pkcs8 pkcs12 pgp dnskey sshkey pem fips-prf gmp xcbc cmac hmac
attr kernel-netlink resolve socket-default stroke updown xauth-generic
xauth-pam xauth-noauth
Dec 10 13:29:53 vpn charon: 00[LIB] unable to load 6 plugin features
(6 due to unmet dependencies)

Er, which plugins?  How do I go about locating what the problem here
is?  Configuration and compilation seemed to run just fine.