Without the ties to PAM we can build eap-gtc on Android

src/frontends/android/jni/Android.mk

@@ -3,7 +3,7 @@ include $(CLEAR_VARS)
 
 strongswan_CHARON_PLUGINS := android-log openssl fips-prf random nonce pubkey \
 	pkcs1 pem xcbc hmac socket-default \
-	eap-identity eap-mschapv2 eap-md5
+	eap-identity eap-mschapv2 eap-md5 eap-gtc
 
 strongswan_PLUGINS := $(strongswan_CHARON_PLUGINS)