execution-engine/Cargo.toml: Restore dependency on ctor.
@@ -27,6 +27,9 @@ std = [
anyhow = { version = "1.0", default-features = false }
byteorder = "1.4.3"
cfg-if = "1"
+# ctor is not used by this crate, but we must prevent other crates from
+# picking up a newer version of this crate which does not work with IceCap:
+ctor = "=0.1.16"
err-derive = "0.2"
lazy_static = { version = "1.4.0", features = ["spin_no_std"] }
num = { version = "0.4", default-features = false }
