diff --git a/Cargo.toml b/Cargo.toml
index 2656b5f..159937f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -93,7 +93,10 @@ optional = true
 default-features = false
 
 [build-dependencies.autocfg]
-version = "1"
+# autocfg 1.4 uses different, non-deterministic filenames. We don't
+# actually depend on these files, but they are present in the out/
+# directory, and it's simpler to keep them around.
+version = "=1.1.0"
 
 [features]
 default = ["std"]