gnu: Add rust-snafu-derive-0.6.

* gnu/packages/crates-io.scm (rust-snafu-derive-0.6): New variable.

gnu/packages/crates-io.scm

@@ -49183,6 +49183,29 @@ control on the fields.")
 clone.")
     (license (list license:expat license:asl2.0))))
 
+(define-public rust-snafu-derive-0.6
+  (package
+    (name "rust-snafu-derive")
+    (version "0.6.10")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (crate-uri "snafu-derive" version))
+       (file-name (string-append name "-" version ".tar.gz"))
+       (sha256
+        (base32 "0nri7ma06g5kimpcdcm8359a55nmps5f3kcngy0j6bin7jhfy20m"))))
+    (build-system cargo-build-system)
+    (arguments
+     `(#:cargo-inputs
+       (("rust-proc-macro2" ,rust-proc-macro2-1)
+        ("rust-quote" ,rust-quote-1)
+        ("rust-syn" ,rust-syn-1))))
+    (home-page "https://github.com/shepmaster/snafu")
+    (synopsis "Ergonomic error handling library")
+    (description "Snafu aims to be an ergonomic error handling library.  This
+package provides derive macros.")
+    (license (list license:expat license:asl2.0))))
+
 (define-public rust-snailquote-0.3
   (package
     (name "rust-snailquote")