Define the toolchain_type used by rust rules. (#129)

katre · acmcarther · commit ab32edea9453 · 2018-10-05T17:10:37.000-07:00
Fixes #128.
diff --git a/rust/BUILD b/rust/BUILD
@@ -7,3 +7,7 @@ exports_files([
     "toolchain.bzl",
     "triple_mappings.bzl",
 ])
+
+toolchain_type(
+    name = "toolchain",
+)
