diff --git a/windows/mpconfigport.h b/windows/mpconfigport.h
index 93b450dbbc..13ba58be13 100644
--- a/windows/mpconfigport.h
+++ b/windows/mpconfigport.h
@@ -119,6 +119,7 @@ void msec_sleep(double msec);
 
 #define restrict
 #define inline                      __inline
+#define alignof(t)                  __alignof(t)
 #define STDIN_FILENO                0
 #define STDOUT_FILENO               1
 #define STDERR_FILENO               2