diff --git a/include/usp10.h b/include/usp10.h
index 79e27bca0a9..9b997c4baf9 100644
--- a/include/usp10.h
+++ b/include/usp10.h
@@ -20,6 +20,11 @@
 #ifndef __USP10_H
 #define __USP10_H
 
+#ifndef __WINESRC__
+# include <windows.h>
+#endif
+/* FIXME: #include <specstrings.h> */
+
 #ifdef __cplusplus
 extern "C" {
 #endif