gnu: Add rust-crossbeam-channel-0.3.

* gnu/packages/crates-io.scm (rust-crossbeam-channel-0.3): New variable.

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

gnu/packages/crates-io.scm

@@ -875,6 +875,38 @@ (define-public rust-criterion-plot-0.3
     (description "Criterion's plotting library.")
     (license (list license:expat license:asl2.0))))
 
+(define-public rust-crossbeam-channel-0.3
+  (package
+    (name "rust-crossbeam-channel")
+    (version "0.3.8")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (crate-uri "crossbeam-channel" version))
+       (file-name
+        (string-append name "-" version ".tar.gz"))
+       (sha256
+        (base32
+         "0azpymyk0ld4akrjfy69ck5pzfgz1f2gb3smm2ywld92vsjd23hg"))))
+    (build-system cargo-build-system)
+    (arguments
+     `(#:skip-build? #t
+       #:cargo-inputs
+       (("rust-crossbeam-utils" ,rust-crossbeam-utils-0.6)
+        ("rust-smallvec" ,rust-smallvec-0.6))
+       #:cargo-development-inputs
+       (("rust-rand" ,rust-rand-0.4)
+        ("rust-signal-hook" ,rust-signal-hook-0.1))))
+    (home-page
+     "https://github.com/crossbeam-rs/crossbeam/tree/master/crossbeam-channel")
+    (synopsis
+     "Multi-producer multi-consumer channels for message passing")
+    (description
+     "Multi-producer multi-consumer channels for message passing.")
+    (license (list license:expat
+                   license:asl2.0
+                   license:bsd-2))))
+
 (define-public rust-crossbeam-deque-0.7
   (package
     (name "rust-crossbeam-deque")