apply a fix for #3611 where the current exception context was deleted with a generator causing a segfault
diff --git a/Python/ceval.c b/Python/ceval.c
index 40ce038..3af0cef 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -2453,7 +2453,7 @@
 
 			if (b->b_type == EXCEPT_HANDLER) {
 				UNWIND_EXCEPT_HANDLER(b);
-				if (why == WHY_EXCEPTION) {
+				if (why == WHY_EXCEPTION && !throwflag) {
 					Py_CLEAR(tstate->exc_type);
 					Py_CLEAR(tstate->exc_value);
 					Py_CLEAR(tstate->exc_traceback);