From Fedora:
https://src.fedoraproject.org/rpms/scim-bridge/c/0532ab48617e02f5bfb1edaba17b22e88d9beaf4
Index: scim-bridge-0.4.16/agent/scim-bridge-agent-signal-listener.cpp
===================================================================
--- scim-bridge-0.4.16.orig/agent/scim-bridge-agent-signal-listener.cpp
+++ scim-bridge-0.4.16/agent/scim-bridge-agent-signal-listener.cpp
@@ -64,7 +64,7 @@ static void sig_quit (int sig)
 {
     if (!signal_occurred) {
         signal_occurred = true;
-        send (pipe_in, '\0', sizeof (char), MSG_NOSIGNAL);
+        send (pipe_in, "", sizeof (char), MSG_NOSIGNAL);
     }
 }