Add a missing volatile qualifier

diff --git a/Upper.xs b/Upper.xs
index 5b0685d97502efdab9caa4a15d4c958615757ccf..2e2c2a523ab1d5de8b6c7ae710c6221a8333d6a0 100644 (file)
--- a/Upper.xs
+++ b/Upper.xs
@@ -2221,7 +2221,7 @@ static I32 su_context_gimme(pTHX_ I32 cxix) {
 
 /* --- Global setup/teardown ----------------------------------------------- */
 
-static U32 su_initialized = 0;
+static VOL U32 su_initialized = 0;
 
 static void su_global_teardown(pTHX_ void *root) {
  if (!su_initialized)