Add SPDX-License-Identifier headers

Add SPDX-License-Identifier headers to all substantial source files.
Collapse copyright years.  Add some Emacs configuration for files
where the copyright notice is at the end.  Add a test that every
file has SPDX-License-Identifier.

1 files changed, 2 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 1af55fc..74e2884 100644
--- a/NEWS
+++ b/NEWS
@@ -28,6 +28,8 @@ wallet 1.4 (unreleased)
     Rename the script to bootstrap from a Git checkout to bootstrap,
     matching the emerging consensus in the Autoconf world.
 
+    Add SPDX-License-Identifier headers to all substantial source files.
+
     Update to rra-c-util 7.2:
 
     * Improve configure output for krb5-config testing.