Issue #14387: Do not include accu.h from Python.h.
diff --git a/Modules/_io/stringio.c b/Modules/_io/stringio.c
index c4794c9..a1c31c0 100644
--- a/Modules/_io/stringio.c
+++ b/Modules/_io/stringio.c
@@ -1,6 +1,7 @@
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
 #include "structmember.h"
+#include "accu.h"
 #include "_iomodule.h"
 
 /* Implementation note: the buffer is always at least one character longer