diff --git a/Cargo.toml b/Cargo.toml
index 49a01237..1b38b8ac 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,7 +17,7 @@ unicode-segmentation = "1.9"
 unicode-normalization = "0.1"
 unicode-case-mapping = "0.4"
 unidecode = "0.3"
-libc = "0.2"
+libc = { version = "0.2", optional = true }
 phf = "0.11"
 serde = { version = "1.0", features = ["derive"], optional = true }
 serde_json = { version = "1.0", optional = true }
@@ -37,6 +37,7 @@ default = []
 name_eq_hash = []
 serialization = ["serde", "serde_json"]
 bench = []
+ffi = ["libc"]
 
 [profile.release]
 lto = "thin"
diff --git a/src/lib.rs b/src/lib.rs
index a635b278..8b6baf81 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -34,6 +34,7 @@ mod title;
 mod transliterate;
 mod word;
 
+#[cfg(feature = "ffi")]
 pub mod external;
 
 #[cfg(feature = "name_eq_hash")]