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, 3 insertions, 0 deletions

diff --git a/contrib/wallet-summary b/contrib/wallet-summary
index ba224d0..8a12294 100755
--- a/contrib/wallet-summary
+++ b/contrib/wallet-summary
@@ -173,6 +173,7 @@ close REPORT;
 
 =for stopwords
 -hm keytab keytabs MERCHANTABILITY NONINFRINGEMENT sublicense Allbery
+SPDX-License-Identifier MIT
 
 =head1 NAME
 
@@ -260,4 +261,6 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 DEALINGS IN THE SOFTWARE.
 
+SPDX-License-Identifier: MIT
+
 =cut