gnu: Add rust-radium-0.5.

* gnu/packages/crates-io.scm (rust-radium-0.5): New variable.

gnu/packages/crates-io.scm

@@ -22818,6 +22818,30 @@ (define-public rust-racer-interner-0.1
 fashion.  It is mostly used in Racer.")
     (license license:expat)))
 
+(define-public rust-radium-0.5
+  (package
+    (name "rust-radium")
+    (version "0.5.3")
+    (source
+      (origin
+        (method url-fetch)
+        (uri (crate-uri "radium" version))
+        (file-name
+         (string-append name "-" version ".tar.gz"))
+        (sha256
+         (base32
+          "1f5vj5zy4kcsw8p87y976dm5pln6v6jfw5f0fkj7qbwfipbsj6wl"))))
+    (build-system cargo-build-system)
+    (arguments
+     `(#:cargo-development-inputs
+       (("rust-static-assertions" ,rust-static-assertions-1))))
+    (home-page "https://github.com/mystor/radium")
+    (synopsis "Portable interfaces for maybe-atomic types")
+    (description
+     "@code{radium} provides abstractions and graceful degradation for behavior
+that must be shared-mutable, but merely may use atomic instructions to do so.")
+    (license license:expat)))
+
 (define-public rust-radix-fmt-1
   (package
     (name "rust-radix-fmt")