diff --git a/include/begin_code.h b/include/begin_code.h
index 63f064b6f8..b1b1a3a9be 100644
--- a/include/begin_code.h
+++ b/include/begin_code.h
@@ -107,7 +107,7 @@
 #ifdef __BORLANDC__
 #pragma nopackwarning
 #endif
-#ifdef _M_X64
+#ifdef _WIN64
 /* Use 8-byte alignment on 64-bit architectures, so pointers are aligned */
 #pragma pack(push,8)
 #else