diff --git a/sdk/include/crt/stdbool.h b/sdk/include/crt/stdbool.h
index 5cb66b55d02..497bb493cb6 100644
--- a/sdk/include/crt/stdbool.h
+++ b/sdk/include/crt/stdbool.h
@@ -28,7 +28,11 @@
 
 /* Don't define bool, true, and false in C++, except as a GNU extension. */
 #ifndef __cplusplus
+#if _MSC_VER <= 1600
+#define bool unsigned char
+#else
 #define bool _Bool
+#endif
 #define true 1
 #define false 0
 #elif defined(__GNUC__) && !defined(__STRICT_ANSI__)