--- a/servo/components/style/build_gecko.rs
+++ b/servo/components/style/build_gecko.rs
@@ -199,25 +199,37 @@ mod bindings {
     }
 
     impl BuilderExt for Builder {
         fn get_initial_builder() -> Builder {
             use bindgen::RustTarget;
 
             // Disable rust unions, because we replace some types inside of
             // them.
-            //
-            // FIXME(emilio, bug 1432153): Make the bindings rustfmt'd on
-            // automation.
             let mut builder = Builder::default()
-                .rustfmt_bindings(false)
                 .rust_target(RustTarget::Stable_1_0);
+            let rustfmt_path = env::var_os("MOZ_AUTOMATION").and_then(|_| {
+                env::var_os("TOOLTOOL_DIR").or_else(|| {
+                    env::var_os("MOZ_SRC")
+                })
+            }).map(PathBuf::from);
+
+            builder = match rustfmt_path {
+                Some(path) => {
+                    builder.with_rustfmt(path.join("rustc").join("bin").join("rustfmt"))
+                },
+                None => {
+                    builder.rustfmt_bindings(env::var_os("STYLO_RUSTFMT_BINDINGS").is_some())
+                }
+            };
+
             for dir in SEARCH_PATHS.iter() {
                 builder = builder.clang_arg("-I").clang_arg(dir.to_str().unwrap());
             }
+
             builder = builder.include(add_include("mozilla-config.h"));
 
             if env::var("CARGO_FEATURE_GECKO_DEBUG").is_ok() {
                 builder = builder.clang_arg("-DDEBUG=1").clang_arg("-DJS_DEBUG=1");
             }
 
             let mut matched_os = false;
             let build_config = CONFIG["build"].as_table().expect("Malformed config file");