fix typo

Doc/api/utilities.tex

@@ -34,7 +34,7 @@ values from C values.
   Return true when the interpreter runs out of stack space.  This is a
   reliable check, but is only available when \constant{USE_STACKCHECK}
   is defined (currently on Windows using the Microsoft Visual \Cpp{}
-  compiler).  \constant{USE_CHECKSTACK} will be
+  compiler).  \constant{USE_STACKCHECK} will be
   defined automatically; you should never change the definition in
   your own code.
 \end{cfuncdesc}