gnu: Add go-github-com-matttproud-golang-protobuf-extensions-pbutil.

* gnu/packages/syncthing.scm
(go-github-com-matttproud-golang-protobuf-extensions-pbutil): New
variable.

gnu/packages/syncthing.scm

@@ -2007,3 +2007,34 @@ data serialization format.")
       (description "This package provides data model artifacts for Prometheus.")
       (home-page "https://github.com/prometheus/client_model")
       (license asl2.0))))
+
+(define-public go-github-com-matttproud-golang-protobuf-extensions-pbutil
+  (let ((commit "c12348ce28de40eed0136aa2b644d0ee0650e56c")
+        (revision "0"))
+    (package
+      (name "go-github-com-matttproud-golang-protobuf-extensions-pbutil")
+      (version (git-version "1.0.0" revision commit))
+      (source
+        (origin
+          (method git-fetch)
+          (uri
+            (git-reference
+              (url "https://github.com/matttproud/golang_protobuf_extensions.git")
+              (commit commit)))
+          (file-name (git-file-name name version))
+          (sha256
+           (base32
+            "1d0c1isd2lk9pnfq2nk0aih356j30k3h1gi2w0ixsivi5csl7jya"))))
+      (build-system go-build-system)
+      (arguments
+       '(#:import-path "github.com/matttproud/golang_protobuf_extensions/pbutil"
+         #:unpack-path "github.com/matttproud/golang_protobuf_extensions"))
+      (propagated-inputs
+       `(("go-github-com-golang-protobuf-proto"
+          ,go-github-com-golang-protobuf-proto)))
+      (synopsis "Streaming Protocol Buffers in Go")
+      (description "This package provides various Protocol Buffer
+extensions for the Go language, namely support for record length-delimited
+message streaming.")
+      (home-page "https://github.com/matttproud/golang_protobuf_extensions")
+      (license asl2.0))))