diff --git a/libc/include/syslog.h b/libc/include/syslog.h
index ee288e5..4b7eecb 100644
--- a/libc/include/syslog.h
+++ b/libc/include/syslog.h
@@ -89,7 +89,11 @@
 void openlog(const char* _Nullable, int, int);
 int setlogmask(int);
 void syslog(int, const char* _Nonnull, ...) __printflike(2, 3);
+#if defined(__arm__) || defined(__aarch64__) || defined(__x86_64__)
 void vsyslog(int, const char* _Nonnull, va_list) __printflike(2, 0);
+#else /* defined(__mips__) || defined(__i386__) */
+void vsyslog(int, const char* _Nonnull, va_list _Nonnull) __printflike(2, 0);
+#endif
 
 __END_DECLS