--- cargo-crates/rug-1.24.0/Cargo.toml.orig
+++ cargo-crates/rug-1.24.0/Cargo.toml
@@ -43,6 +43,7 @@
 version = "~1.6"
 optional = true
 default-features = false
+features = [ "use-system-libs" ]
 
 [dependencies.libc]
 version = "0.2.44"