[PATCH 20/86] gnu: Add rust-cfg-if.

[ng0]

* gnu/packages/rust.scm (rust-cfg-if): New variable.
---
 gnu/packages/rust.scm | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/gnu/packages/rust.scm b/gnu/packages/rust.scm
index 910f296b6..365ab4ed4 100644
--- a/gnu/packages/rust.scm
+++ b/gnu/packages/rust.scm
@@ -682,3 +682,26 @@ per-object thread-local storage, unlike the standard 
library's
 @code{thread_local!} macro which only allows static thread-local
 storage.")
     (license (list license:asl2.0 license:expat))))
+
+(define-public rust-cfg-if
+  (package
+    (name "rust-cfg-if")
+    (version "0.1.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (crate-uri "cfg-if" version))
+       (file-name
+        (string-append name "-" version ".tar.gz"))
+       (sha256
+        (base32
+         "137qikjcal4h75frzcn6mknygqk8vy5bva7w851aydb5gc6pc7ny"))))
+    (build-system cargo-build-system)
+    (home-page "https://github.com/alexcrichton/cfg-if";)
+    (synopsis
+     "Ergonomically define an item depending on a large number of 
@code{#[cfg]} parameters")
+    (description
+     "Cfg-if provides a macro to ergonomically define an item depending
+on a large number of @code{#[cfg]} parameters.  Structured like an
+if-else chain, the first matching branch is the item that gets emitted.")
+    (license (list license:expat license:asl2.0))))
-- 
2.11.0