gnu: Add go-github-com-d4l3k-messagediff.

* gnu/packages/syncthing.scm (go-github-com-d4l3k-messagediff): New variable.

gnu/packages/syncthing.scm

@@ -117,3 +117,27 @@ marshalling and unmarshalling library in Go.  It uses code generation and not
 reflection.")
       (home-page "https://github.com/calmh/xdr")
       (license expat))))
+
+(define-public go-github-com-d4l3k-messagediff
+  (let ((commit "29f32d820d112dbd66e58492a6ffb7cc3106312b")
+        (revision "0"))
+    (package
+      (name "go-github-com-d4l3k-messagediff")
+      (version (git-version "1.1.0" revision commit))
+      (source (origin
+                (method git-fetch)
+                (uri (git-reference
+                       (url "https://github.com/d4l3k/messagediff")
+                       (commit commit)))
+                (file-name (git-file-name name version))
+                (sha256
+                 (base32
+                  "104hl8x57ciaz7mzafg1vp9qggxcyfm8hsv9bmlihbz9ml3nyr8v"))))
+      (build-system go-build-system)
+      (arguments
+        `(#:import-path "github.com/d4l3k/messagediff"))
+      (synopsis "Diff arbitrary Go structs")
+      (description "Messagediff is a library for calculating diffs of arbitrary
+structs in the Go programming language.")
+      (home-page "https://github.com/d4l3k/messagediff")
+      (license expat))))