Ignore SIGPIPE on systems that have it.

According to the GTK+ docs, gtk_init calls "signal(SIGPIPE, SIG_IGN)" at
startup. Replicate that behavior here, otherwise we tend to terminate
unexpectedly.

Change-Id: Ia017402755d647e6050af40deacef6765eea8694
Reviewed-on: https://code.wireshark.org/review/1614
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Tested-by: Gerald Combs <gerald@wireshark.org>

ui/qt/main.cpp

@@ -29,6 +29,8 @@
 
 #include <glib.h>
 
+#include <signal.h>
+
 #ifndef HAVE_GETOPT
 #  include "wsutil/wsgetopt.h"
 #else
@@ -784,6 +786,11 @@ int main(int argc, char *argv[])
       wsApp->setLastOpenDir(get_persdatafile_dir());
     }
 
+#ifdef Q_OS_UNIX
+    // Replicates behavior in gtk_init();
+    signal(SIGPIPE, SIG_IGN);
+#endif
+
 #ifdef HAVE_LIBPCAP
     capture_callback_add(main_capture_callback, NULL);
 #endif