init: Ignore SIGPIPE

Ignore SIGPIPE on all non-win32 OSes, otherwise an unexpectedly disconnecting
RPC client will terminate the application. This problem was introduced
with the libhttp-based RPC server.

Fixes #6660.

src/init.cpp

@@ -687,10 +687,8 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
     sa_hup.sa_flags = 0;
     sigaction(SIGHUP, &sa_hup, NULL);
 
-#if defined (__SVR4) && defined (__sun)
-    // ignore SIGPIPE on Solaris
+    // Ignore SIGPIPE, otherwise it will bring the daemon down if the client closes unexpectedly
     signal(SIGPIPE, SIG_IGN);
-#endif
 #endif
 
     // ********************************************************* Step 2: parameter interactions