Fix missing cast

Author: markshannon

Include/cpython/pystate.h

@@ -112,7 +112,7 @@ struct _ts {
     int py_recursion_remaining;
     int py_recursion_limit;
 
-    int c_recursion_remaining;
+    int c_recursion_remaining; /* Retained for backwards compatibility. Do not use */
     int recursion_headroom; /* Allow 50 more calls to handle any errors. */
 
     /* 'tracing' keeps track of the execution depth when tracing/profiling.

Python/pythonrun.c

@@ -1543,10 +1543,11 @@ int PyOS_CheckStack(void)
     char here;
     uintptr_t here_addr = (uintptr_t)&here;
     PyThreadState *tstate = _PyThreadState_GET();
-    if (tstate->c_stack_hard_limit == 0) {
+    _PyThreadStateImpl *_tstate = (_PyThreadStateImpl *)tstate;
+    if (_tstate->c_stack_hard_limit == 0) {
         _Py_InitializeRecursionLimits(tstate);
     }
-    if (here_addr >= tstate->c_stack_soft_limit) {
+    if (here_addr >= _tstate->c_stack_soft_limit) {
         return 0;
     }
     else {