diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
index e1688bfeee9..fb018dc0538 100644
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@@ -17,7 +17,7 @@ path = "lib.rs"
 doctest = false
 
 [features]
-gecko = ["style_traits/gecko", "bindgen", "regex", "toml", "num_cpus", "mozbuild"]
+gecko = ["style_traits/gecko", "bindgen", "regex", "toml", "mozbuild"]
 servo = [
     "serde",
     "style_traits/servo",
@@ -59,7 +59,7 @@ new_debug_unreachable = "1.0"
 num-derive = "0.3"
 num-integer = "0.1"
 num-traits = "0.2"
-num_cpus = { version = "1.1.0", optional = true }
+num_cpus = { version = "1.1.0" }
 owning_ref = "0.4"
 parking_lot = "0.12"
 precomputed-hash = "0.1.1"
diff --git a/components/style/global_style_data.rs b/components/style/global_style_data.rs
index eda1d771a6b..eebe27fe30f 100644
--- a/components/style/global_style_data.rs
+++ b/components/style/global_style_data.rs
@@ -114,7 +114,8 @@ impl StyleThreadPool {
 
 #[cfg(feature = "servo")]
 fn stylo_threads_pref() -> i32 {
-    pref!(layout.threads)
+    use servo_config::pref;
+    pref!(layout.threads) as i32
 }
 
 #[cfg(feature = "gecko")]