gnu: Add rust-rayon-core-1.7.

* gnu/packages/crates-io.scm (rust-rayon-core-1.7): New variable.
(rust-rayon-core-1.5): Inherit from rust-rayon-core-1.7.

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

gnu/packages/crates-io.scm

@@ -8185,8 +8185,41 @@ accessors.")
      "Simple work-stealing parallelism for Rust.")
     (license (list license:asl2.0 license:expat))))
 
+(define-public rust-rayon-core-1.7
+  (package
+    (name "rust-rayon-core")
+    (version "1.7.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (crate-uri "rayon-core" version))
+       (file-name
+        (string-append name "-" version ".tar.gz"))
+       (sha256
+        (base32
+         "1ac55kpnh2390ah7r071vnjbiy308qpznql0n597x5dgxx39pa08"))))
+    (build-system cargo-build-system)
+    (arguments
+     `(#:skip-build? #t
+       #:cargo-inputs
+       (("rust-crossbeam-deque" ,rust-crossbeam-deque-0.7)
+        ("rust-crossbeam-queue" ,rust-crossbeam-queue-0.2)
+        ("rust-crossbeam-utils" ,rust-crossbeam-utils-0.7)
+        ("rust-lazy-static" ,rust-lazy-static-1.3)
+        ("rust-num-cpus" ,rust-num-cpus-1.10))
+       #:cargo-development-inputs
+       (("rust-libc" ,rust-libc-0.2)
+        ("rust-rand" ,rust-rand-0.7)
+        ("rust-rand-xorshift" ,rust-rand-xorshift-0.2)
+        ("rust-scoped-tls" ,rust-scoped-tls-1.0))))
+    (home-page "https://github.com/rayon-rs/rayon")
+    (synopsis "Core APIs for Rayon")
+    (description "Core APIs for Rayon.")
+    (license (list license:expat license:asl2.0))))
+
 (define-public rust-rayon-core-1.5
   (package
+    (inherit rust-rayon-core-1.7)
     (name "rust-rayon-core")
     (version "1.5.0")
     (source
@@ -8198,7 +8231,6 @@ accessors.")
        (sha256
         (base32
          "1ljva6blaf1wmzvg77h1i9pd0hsmsbbcmdk7sjbw7h2s8gw0vgpb"))))
-    (build-system cargo-build-system)
     (arguments
      `(#:skip-build? #t
        #:cargo-inputs
@@ -8211,11 +8243,7 @@ accessors.")
        (("rust-libc" ,rust-libc-0.2)
         ("rust-rand" ,rust-rand-0.4)
         ("rust-rand-xorshift" ,rust-rand-xorshift-0.2)
-        ("rust-scoped-tls" ,rust-scoped-tls-1.0))))
-    (home-page "https://github.com/rayon-rs/rayon")
-    (synopsis "Core APIs for Rayon")
-    (description "Core APIs for Rayon.")
-    (license (list license:expat license:asl2.0))))
+        ("rust-scoped-tls" ,rust-scoped-tls-1.0))))))
 
 (define-public rust-rdrand-0.4
   (package