diff --git a/libs/platform/string.h b/libs/platform/string.h
index 7f0876587..be2e976b2 100644
--- a/libs/platform/string.h
+++ b/libs/platform/string.h
@@ -9,7 +9,7 @@
 #include <string.h>
 #if (defined(__APPLE__) && __MAC_OS_X_VERSION_MIN_REQUIRED < 1070) || defined(__MINGW32__)
 // need our own implementation of strnlen
-#ifdef __MINGW32__ && !__MINGW64__
+#if defined(__MINGW32__) && !defined(__MINGW64__)
 static size_t strnlen(const char *s, size_t n)
 {
     const char *p = (const char *)memchr(s, 0, n);