Stub out libevent's signal.c.

third_party/libevent/nacl_nonsfi/signal_stub.c

Index: third_party/libevent/nacl_nonsfi/signal_stub.c
diff --git a/third_party/libevent/nacl_nonsfi/signal_stub.c b/third_party/libevent/nacl_nonsfi/signal_stub.c
new file mode 100644
index 0000000000000000000000000000000000000000..56208bc13e79c9fd5d4866e07ac248f62b4acb0f
--- /dev/null
+++ b/third_party/libevent/nacl_nonsfi/signal_stub.c
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2015 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/*
+ * In nacl_helper_nonsfi, socketpair() is unavailable. In libevent, it is used
+ * to notify signal handler invocation, which is unused in nacl_helper_nonsfi.

[Mark Seaborn, 2015/04/24 16:01:54]

Nit: "notify of a signal handler invocation"?

[hidehiko, 2015/04/27 16:47:21]

Done.

+ * Unfortunately, there is no macro to disable the feature, so we stub out
+ * the signal module entirely.
+ */
+
+struct event_base;

[Mark Seaborn, 2015/04/24 16:01:54]

Nit: #include libevent/evsignal.h instead.

That way you get a check that the functions below have the right type
signatures.

[hidehiko, 2015/04/27 16:47:21]

Done.

+struct event;
+
+struct event_base *evsignal_base = 0;
+
+int evsignal_init(struct event_base *base) {
+  return -1;

[Mark Seaborn, 2015/04/24 16:01:54]

Nit: This indicates an error.  Though none of the callers actually check the
return value. :-(  Should probably be "return 0" instead.

[hidehiko, 2015/04/27 16:47:21]

Done.

+}
+
+void evsignal_process(struct event_base *base) {
+}
+
+int evsignal_add(struct event *event) {
+  return -1;
+}
+
+int evsignal_del(struct event *event) {
+  return -1;
+}
+
+void evsignal_dealloc(struct event_base *base) {
+}