fixes #748 Minor warning in windows build of IPC test
diff --git a/tests/ipc.c b/tests/ipc.c
index 7569376..d086ffb 100644
--- a/tests/ipc.c
+++ b/tests/ipc.c
@@ -37,7 +37,9 @@
     int sc;
     int i;
     int s1, s2;
+#if !defined(NN_HAVE_WINDOWS)
     int rc;
+#endif
 
     int size;
     char * buf;