eap-aka-3gpp: Add plugin that implements 3GPP MILENAGE algorithm in software

This is similar to the eap-aka-3gpp2 plugin. K (optionally concatenated
with OPc) may be configured as binary EAP secret in ipsec.secrets or
swanctl.conf.

Based on a patch by Thomas Strangert.

Fixes #2326.

src/libcharon/Makefile.am

@@ -370,6 +370,13 @@ if MONOLITHIC
 endif
 endif
 
+if USE_EAP_AKA_3GPP
+  SUBDIRS += plugins/eap_aka_3gpp
+if MONOLITHIC
+  libcharon_la_LIBADD += plugins/eap_aka_3gpp/libstrongswan-eap-aka-3gpp.la
+endif
+endif
+
 if USE_EAP_AKA_3GPP2
   SUBDIRS += plugins/eap_aka_3gpp2
 if MONOLITHIC