diff --git a/src/os_win32.h b/src/os_win32.h
index 3cc0f47..7f9ee8d 100644
--- a/src/os_win32.h
+++ b/src/os_win32.h
@@ -86,6 +86,10 @@
 #endif
 #ifndef PROTO
 # include <windows.h>
+
+// Weird: rpcndr.h defines "small" to "char", which causes trouble
+#undef small
+
 # ifndef SM_CXPADDEDBORDER
 #  define SM_CXPADDEDBORDER     92
 # endif