Update stdlib.bzl
diff --git a/go/private/actions/stdlib.bzl b/go/private/actions/stdlib.bzl
index 2ca4281..0069aa0 100644
--- a/go/private/actions/stdlib.bzl
+++ b/go/private/actions/stdlib.bzl
@@ -92,6 +92,7 @@
 
 def _build_env(go):
     env = go.env
+    env["GOROOT"] = go.sdk.root_file.dirname
 
     if go.mode.pure:
         env.update({"CGO_ENABLED": "0"})