Index: source/Host/common/MainLoop.cpp
===================================================================
--- source/Host/common/MainLoop.cpp
+++ source/Host/common/MainLoop.cpp
@@ -155,7 +155,9 @@
 
 sigset_t MainLoop::RunImpl::get_sigmask() {
 #if SIGNAL_POLLING_UNSUPPORTED
-  return 0;
+  sigset_t sigmask;
+  memset(sigmask.__val, 0, _SIGSET_NWORDS);
+  return sigmask;
 #else
   sigset_t sigmask;
   int ret = pthread_sigmask(SIG_SETMASK, nullptr, &sigmask);