From 0ebc33e079fa41225ca4f1f817abd2778c68d24e Mon Sep 17 00:00:00 2001
From: Kevin Reid <kpreid@switchb.org>
Date: Mon, 10 Jul 2023 19:41:19 -0700
Subject: [PATCH] Use `const` thread local initialization.

This is newly documented but not new:
https://github.com/rust-lang/rust/pull/110620
---
 all-is-cubes/src/save/conversion.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/all-is-cubes/src/save/conversion.rs b/all-is-cubes/src/save/conversion.rs
index f29d7087b..16b235b85 100644
--- a/all-is-cubes/src/save/conversion.rs
+++ b/all-is-cubes/src/save/conversion.rs
@@ -821,7 +821,9 @@ mod universe {
         /// TODO: Find an alternative not dependent on external state. Perhaps
         /// serde::DeserializeSeed will do, or if necessary we can modify URef to support
         /// modification after construction.
-        static UREF_DESERIALIZATION_CONTEXT: RefCell<Option<DeContext>> = RefCell::new(None);
+        static UREF_DESERIALIZATION_CONTEXT: RefCell<Option<DeContext>> = const {
+            RefCell::new(None)
+        };
     }
 
     struct DeContext {