gnu: Add rust-runtime-0.3.

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

gnu/packages/crates-io.scm

@@ -29623,6 +29623,35 @@ console applications.")
         (base32
          "1v255xqkig5lwnczvm3achydhxx6kf9jcdxdlgzndgpd18bp6x6k"))))))
 
+(define-public rust-runtime-0.3
+  (package
+    (name "rust-runtime")
+    (version "0.3.0-alpha.8")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (crate-uri "runtime" version))
+       (file-name (string-append name "-" version ".tar.gz"))
+       (sha256
+        (base32 "04aj2jslnndwhhbvp9ysdgh98vfy6lk6f0rzqsan5wlfpd70nzc3"))))
+    (build-system cargo-build-system)
+    (arguments
+     `(#:skip-build? #t
+       #:cargo-inputs
+       (("rust-futures-preview" ,rust-futures-preview-0.3)
+        ("rust-pin-project" ,rust-pin-project-0.4)
+        ("rust-runtime-attributes" ,rust-runtime-attributes-0.3)
+        ("rust-runtime-native" ,rust-runtime-native-0.3)
+        ("rust-runtime-raw" ,rust-runtime-raw-0.3))))
+    (home-page "https://github.com/rustasync/runtime")
+    (synopsis "Empowering everyone to build asynchronous software")
+    (description
+     "Runtime is an asynchronous library.
+
+This package is deprecated.  If you're looking for an asynchronous runtime
+please consider using @code{async-std} or @code{tokio}.")
+    (license (list license:expat license:asl2.0))))
+
 (define-public rust-runtime-attributes-0.3
   (package
     (name "rust-runtime-attributes")