gnu: Add rust-arr-macro-impl-0.1.

* gnu/packages/crates-io.scm (rust-arr-macro-impl-0.1): New variable.

gnu/packages/crates-io.scm

@@ -3358,6 +3358,29 @@ coverage-guided, mutation-based fuzzers.")
 that runs on Argon2.")
     (license license:expat)))
 
+(define-public rust-arr-macro-impl-0.1
+  (package
+    (name "rust-arr-macro-impl")
+    (version "0.1.3")
+    (source (origin
+              (method url-fetch)
+              (uri (crate-uri "arr_macro_impl" version))
+              (file-name (string-append name "-" version ".tar.gz"))
+              (sha256
+               (base32
+                "1lbjilz3pvwav72dfkcbz99rsq7m04xbdpqh8g3yvx3jsn5wf286"))))
+    (build-system cargo-build-system)
+    (arguments
+     `(#:cargo-inputs
+       (("rust-proc-macro-hack" ,rust-proc-macro-hack-0.5)
+        ("rust-quote" ,rust-quote-1)
+        ("rust-syn" ,rust-syn-1))))
+    (home-page "https://github.com/JoshMcguigan/arr_macro")
+    (synopsis "Private impl crate for arr_macro")
+    (description "This package provides a private @code{impl} crate for
+@code{arr_macro}.")
+    (license (list license:expat license:asl2.0))))
+
 (define-public rust-array-macro-1
   (package
     (name "rust-array-macro")