Add the fault handler in order to try to get a proper crash stack

gns3server/crash_report.py

@@ -19,6 +19,10 @@ import os
 import sys
 import struct
 import platform
+import faulthandler
+
+# Display a traceback in case of segfault crash. Usefull when frozen
+faulthandler.enable()
 
 try:
     import raven

gns3server/main.py

@@ -190,6 +190,8 @@ def main():
     port = int(server_config["port"])
     server = Server.instance(host, port)
     try:
+        import faulthandler
+        faulthandler._sigsegv()
         server.run()
     except OSError as e:
         # This is to ignore OSError: [WinError 0] The operation completed successfully exception on Windows.