diff --git a/src/runtime/cgo/gcc_clearenv.c b/src/runtime/cgo/gcc_clearenv.c
index 7657e3562d..c4f69c1e00 100644
--- a/src/runtime/cgo/gcc_clearenv.c
+++ b/src/runtime/cgo/gcc_clearenv.c
@@ -10,7 +10,7 @@
 
 /* Stub for calling clearenv */
 void
-x_cgo_clearenv(void **_unused)
+x_cgo_clearenv(void **env __attribute__((unused)))
 {
 	_cgo_tsan_acquire();
 	clearenv();