gnu: Add rust-rustc-hex-1.

* gnu/packages/crates-io.scm (rust-rustc-hex-1): New variable.

Change-Id: Ibd2b1305acc489276ec17c966887e300beccf443

gnu/packages/crates-io.scm

@@ -60542,6 +60542,20 @@ It is automatically published using the compiler repository at
 hex conversion traits.")
     (license (list license:expat license:asl2.0))))
 
+(define-public rust-rustc-hex-1
+  (package
+    (inherit rust-rustc-hex-2)
+    (name "rust-rustc-hex")
+    (version "1.0.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (crate-uri "rustc-hex" version))
+       (file-name (string-append name "-" version ".tar.gz"))
+       (sha256
+        (base32 "07pff94vqc1mhrqp9i06xzayiad4xfx7588zkqsdw875lpkqrsqc"))))
+    (arguments (list #:tests? #f))))    ; Test suite can't find the package itself.
+
 (define-public rust-rustc-rayon-0.5
   (package
     (name "rust-rustc-rayon")