gnu: Add rust-multi-default-trait-impl-0.1.

* gnu/packages/crates-io.scm (rust-multi-default-trait-impl-0.1): New variable.

Signed-off-by: Efraim Flashner <efraim@flashner.co.il>

gnu/packages/crates-io.scm

@@ -9,6 +9,7 @@
 ;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
 ;;; Copyright © 2020 Leo Famulari <leo@famulari.name>
 ;;; Copyright © 2020 Gabriel Arazas <foo.dogsquared@gmail.com>
+;;; Copyright © 2020 André Batista <nandre@riseup.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -14633,6 +14634,34 @@ checking.")
       "Chaining APIs for both self -> Self and &mut self methods.")
     (license license:expat)))
 
+(define-public rust-multi-default-trait-impl-0.1
+  (package
+    (name "rust-multi-default-trait-impl")
+    (version "0.1.2")
+    (source
+      (origin
+        (method url-fetch)
+        (uri (crate-uri "multi-default-trait-impl" version))
+        (file-name
+         (string-append name "-" version ".tar.gz"))
+        (sha256
+         (base32
+          "1r6y5zb6kg655zi02yk4amkwsgds5ay9ag1dk30cls7rn3dlvvqs"))))
+    (build-system cargo-build-system)
+    (arguments
+     `(#:cargo-inputs
+       (("rust-lazy-static" ,rust-lazy-static-1)
+        ("rust-proc-macro2" ,rust-proc-macro2-1)
+        ("rust-quote" ,rust-quote-1)
+        ("rust-syn" ,rust-syn-1))))
+    (home-page "https://github.com/hainish/multi-default-trait-impl")
+    (synopsis "Define multiple implementations of trait")
+    (description
+     "This library contains two attribute macros: @code{default_trait_impl}
+which defines a default trait implementation, and @code{trait_impl} which uses
+a default trait implementation you've defined.")
+    (license license:lgpl2.1+)))
+
 (define-public rust-nasm-rs-0.1
   (package
     (name "rust-nasm-rs")