diff --git a/src/xpdev/rwlockwrap.c b/src/xpdev/rwlockwrap.c
index cc90610d0fd34070446d1c5e65947b346bc98c74..b0a9ef152dd67773a774244f573b893b710cb342 100644
--- a/src/xpdev/rwlockwrap.c
+++ b/src/xpdev/rwlockwrap.c
@@ -2,6 +2,8 @@
 
 #ifdef _WIN32
 
+#include "gen_defs.h"	// For windows.h
+
 bool
 rwlock_init(rwlock_t *lock)
 {