+# Copyright © 2020 Nick Bowler
+#
+# This program 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.
+#
+# This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
+
+AT_BANNER([C declarations])
+
+m4_define([CHECK_DECL],
+[AT_DATA([expout], [[$2]m4_newline])
+AT_CHECK([cdecl99 -e 'explain $1'], [0], [expout])])
+
+m4_define([SIMPLE_DECL],
+[AT_SETUP([$1])
+CHECK_DECL([$1], [$2])
+AT_CLEANUP])
+
+SIMPLE_DECL([int (x*)], [type function (pointer to x) returning int])