Fix some dependencies and warnings in small config
diff --git a/library/pkparse.c b/library/pkparse.c
index 9160e85..2ecf143 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -745,7 +745,10 @@
     }
     else
 #endif /* POLARSSL_PKCS5_C */
+    {
+        ((void) pwd);
         return( POLARSSL_ERR_PK_FEATURE_UNAVAILABLE );
+    }
 
     return( pk_parse_key_pkcs8_unencrypted_der( pk, buf, len ) );
 }