diff --git a/libc/include/bits/signal.h b/libc/include/bits/signal.h
index 2cf92f99..423787e1 100644
--- a/libc/include/bits/signal.h
+++ b/libc/include/bits/signal.h
@@ -15,7 +15,11 @@ struct sigaction
     __simple_sighandler_t sa_handler;
     sigset_t sa_mask;
     int sa_flags;
+#ifdef __cplusplus
     void* __sa_sigreturn = nullptr;
+#else
+    void* __sa_sigreturn;
+#endif
 };
 
 // Constants for the 'how' parameter in sigprocmask().