diff --git a/src/wintype.h b/src/wintype.h
index 8fa5cd8..01a2401 100644
--- a/src/wintype.h
+++ b/src/wintype.h
@@ -133,8 +133,12 @@ typedef UINT64 TIMESTAMP;
 
 #define MAKEBOOL(val)     ((val) ? TRUE : FALSE)
 #define OFFSETOF(struc, field)   ((UINT_PTR)(&(((struc *)0)->field)))
+#ifndef MIN
 #define MIN(x, y)         (((x) < (y)) ? (x) : (y))
+#endif
+#ifndef MAX
 #define MAX(x, y)         (((x) > (y)) ? (x) : (y))
+#endif
 
 #define MAKEWORD(a, b)    ((WORD)((((UINT_PTR)(a)) & 0xFF) | ((((UINT_PTR)(b)) & 0xFF) << 8)))
 #define MAKELONG(a, b)    ((LONG)((((UINT_PTR)(a)) & 0xFFFF) | ((((UINT_PTR)(b)) & 0xFFFF) << 16)))