m4: Rename compat.at to compat.m4.

This is used by both Autoconf and Autotest, so it doesn't make sense for
it to have a .at (Autotest) extension.

Signed-off-by: Ben Pfaff <blp@ovn.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/m4/compat.m4 b/m4/compat.m4
new file mode 100644
index 000000000..78da7a97e
--- /dev/null
+++ b/m4/compat.m4
@@ -0,0 +1,17 @@
+# -*- autoconf -*-
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+m4_ifndef([AS_VAR_COPY],
+  [m4_define([AS_VAR_COPY],
+    [AS_LITERAL_IF([$1[]$2], [$1=$$2], [eval $1=\$$2])])])