mes: nyacc compat18: Add placeholder.

* mes/module/nyacc/compat18.scm: New file.

mes/module/nyacc/compat18.scm

@@ -0,0 +1,27 @@
+;;; GNU Mes --- Maxwell Equations of Software
+;;; Copyright © 2022 Timothy Sample <samplet@ngyro.com>
+;;;
+;;; This file is part of GNU Mes.
+;;;
+;;; GNU Mes is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Mes is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;;
+;;; Nyacc loads this module from the 'else' clause of some 'cond-expand'
+;;; forms.  It is for Guile 1.8 compatibility.  We already provide
+;;; everything that Nyacc needs, so we stub this module out.
+;;;
+;;; Code:
+
+(define-module (nyacc compat18))