Upstream bugs:
https://bugs.gentoo.org/678410
https://bugs.python.org/issue23395

This patch fixes some spurious exceptions caused by interrupts
that don't have a handler registered in some situations.

diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index 0b9e8f1..f161e18 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -1575,7 +1575,10 @@ PyErr_CheckSignals(void)
 void
 PyErr_SetInterrupt(void)
 {
-    trip_signal(SIGINT);
+    if ((Handlers[SIGINT].func != IgnoreHandler) &&
+        (Handlers[SIGINT].func != DefaultHandler)) {
+        trip_signal(SIGINT);
+    }
 }
 
 void