diff --git a/library/aesni.c b/library/aesni.c
index 5f25a82..7eb11af 100644
--- a/library/aesni.c
+++ b/library/aesni.c
@@ -53,7 +53,7 @@
     if (!done) {
 #if MBEDTLS_AESNI_HAVE_CODE == 2
         static unsigned info[4] = { 0, 0, 0, 0 };
-#if defined(_MSC_VER)
+#if defined(_WIN32)
         __cpuid(info, 1);
 #else
         __cpuid(1, info[0], info[1], info[2], info[3]);