arb crash caused by truncated user properties

[westram]

reproduce:

• use attached properties​
• run demo.arb

⇒ instant crash of r17600 with

> arb demo.arb
Using ARBHOME='/arb'
Using properties from /home/user/.arb_prop
Please wait while the program ARB is starting .....
Waiting for '/home/user/.arb_tmp/sockets/arb_launcher.38978'..
Thu Nov 15 16:06:09 CET 2018 arb server.log created by arb_launcher
[arb_launcher[0]: log for ARB_PID='38978']
[arb_launcher[0]: Starting 'arb_ntree demo.arb'..]
Using properties from '/home/user/.arb_prop/ntree.arb'
Using properties from '/arb/lib/arb_default/status.arb'
*** buffer overflow detected ***: arb_ntree terminated
/arb/bin/arb_launcher: line 25: 39070 Aborted                 (core dumped) $CMD
[arb_launcher[0]: 'arb_ntree demo.arb' has terminated with error 134]
[arb_launcher[0]: Still have 1 arb processes..]
[arb_launcher[0]: All launched processes terminated]
[arb_launcher[0]: cleaning up arb session]
[...]
ARB crashed :-(
[...]

wanted behavior:

• arb shall detect that property file is defect,
• report an error and
• advice what to do, e.g.
  • delete (=revert to defaults) or
  • restore (from backup)

---

follow-up-of: #799

[westram]

truncated properties