Check the return code for PyErr_Warn() when warning about raising string
exceptions.  This was triggered when 'warnings' had a filter set to "error"
that caught the string exception deprecation warning.
diff --git a/Misc/NEWS b/Misc/NEWS
index 4e16038..3ad50b5 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@
 Core and builtins
 -----------------
 
+- Properly check if 'warnings' raises an exception (usually when a filter set
+  to "error" is triggered) when raising a warning for raising string
+  exceptions.
+
 - CO_GENERATOR_ALLOWED is no longer defined, this behavior is the default.
   The name was removed from Include/code.h.