diff --git a/dune-project b/dune-project
index 3828727..f7f1657 100644
--- a/dune-project
+++ b/dune-project
@@ -25,7 +25,8 @@
  (depends
   (dune (> 2.5))
   (posix-base (= :version))
-  ctypes)
+  ctypes
+  unix-errno)
 )
 
 (package
diff --git a/posix-signal.opam b/posix-signal.opam
index 97f76d3..796914b 100644
--- a/posix-signal.opam
+++ b/posix-signal.opam
@@ -13,6 +13,7 @@ depends: [
   "dune" {> "2.5"}
   "posix-base" {= version}
   "ctypes"
+  "unix-errno"
 ]
 build: [
   ["dune" "subst"] {pinned}