time support: check and define NDN_CPP_HAVE_GMTIME_SUPPORT. In ndn_toIsoString and ndn_fromIsoString, return an error if not supported.
diff --git a/ndn-cpp/c/errors.h b/ndn-cpp/c/errors.h
index f975c26..396f43d 100644
--- a/ndn-cpp/c/errors.h
+++ b/ndn-cpp/c/errors.h
@@ -45,7 +45,8 @@
NDN_ERROR_SocketTransport_error_in_poll,
NDN_ERROR_SocketTransport_error_in_recv,
NDN_ERROR_SocketTransport_error_in_close,
- NDN_ERROR_Name_component_does_not_begin_with_the_expected_marker
+ NDN_ERROR_Name_component_does_not_begin_with_the_expected_marker,
+ NDN_ERROR_Time_functions_are_not_supported_by_the_standard_library
} ndn_Error;
/**