diff --git a/dune-project b/dune-project
index 61db306..f4113b3 100644
--- a/dune-project
+++ b/dune-project
@@ -54,6 +54,7 @@
    (ocaml (>= 4.08))
    (trace (= :version))
    (mtime (>= 2.0))
+   thread-local-storage
    base-bigarray
    base-unix
    dune)
diff --git a/trace-fuchsia.opam b/trace-fuchsia.opam
index 62ef782..476cfba 100644
--- a/trace-fuchsia.opam
+++ b/trace-fuchsia.opam
@@ -13,6 +13,7 @@ depends: [
   "ocaml" {>= "4.08"}
   "trace" {= version}
   "mtime" {>= "2.0"}
+  "thread-local-storage"
   "base-bigarray"
   "base-unix"
   "dune" {>= "2.9"}