gnu: Add rust-rustc-rayon-core-0.3.

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

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

gnu/packages/crates-io.scm

@@ -20353,6 +20353,42 @@ It is automatically published using the compiler repository at
      "This package provides a speedy, non-cryptographic hash used in rustc.")
     (license (list license:asl2.0 license:expat))))
 
+(define-public rust-rustc-rayon-core-0.3
+  (package
+    (name "rust-rustc-rayon-core")
+    (version "0.3.0")
+    (source
+      (origin
+        (method url-fetch)
+        (uri (crate-uri "rustc-rayon-core" version))
+        (file-name
+         (string-append name "-" version ".tar.gz"))
+        (sha256
+         (base32
+          "1cwc50mcclzfmhmi87953fjk6cc9ppmchn9mlwzfllq03y1jf97a"))))
+    (build-system cargo-build-system)
+    (arguments
+     `(#:tests? #f
+       #:cargo-inputs
+       (("rust-crossbeam-deque" ,rust-crossbeam-deque-0.7)
+        ("rust-crossbeam-queue" ,rust-crossbeam-queue-0.1)
+        ("rust-crossbeam-utils" ,rust-crossbeam-utils-0.6)
+        ("rust-lazy-static" ,rust-lazy-static-1)
+        ("rust-num-cpus" ,rust-num-cpus-1))
+       #:cargo-development-inputs
+       (("rust-libc" ,rust-libc-0.2)
+        ("rust-rand" ,rust-rand-0.6)
+        ("rust-rand-xorshift" ,rust-rand-xorshift-0.1)
+        ("rust-scoped-tls" ,rust-scoped-tls-1.0))))
+    (home-page "https://github.com/rust-lang/rustc-rayon")
+    (synopsis "Core APIs for Rayon - fork for rustc")
+    (description
+     "Note: This package is an unstable fork made for use in rustc
+
+Rayon-core represents the \"core, stable\" APIs of Rayon: join, scope, and so
+forth, as well as the ability to create custom thread-pools with ThreadPool.")
+    (license (list license:asl2.0 license:expat))))
+
 (define-public rust-rustc-serialize-0.3
   (package
     (name "rust-rustc-serialize")