#8862: Fix curses cleanup with getchar is interrupted by a signal.

I have no idea how one would write a test for this.

Patch by July Tikhonov.
diff --git a/Modules/_cursesmodule.c b/Modules/_cursesmodule.c
index 5e1afa9..d1dedb0 100644
--- a/Modules/_cursesmodule.c
+++ b/Modules/_cursesmodule.c
@@ -895,7 +895,9 @@
     }
     if (rtn == ERR) {
         /* getch() returns ERR in nodelay mode */
-        PyErr_SetString(PyCursesError, "no input");
+        PyErr_CheckSignals();
+        if (!PyErr_Occurred())
+            PyErr_SetString(PyCursesError, "no input");
         return NULL;
     } else if (rtn<=255) {
         return Py_BuildValue("C", rtn);