Describe the bug
Setting PTT control to udev alias seg faults JS8Call

To Reproduce

1. Make a udev rule (in this case Rigblaster P&P)
   KERNEL=="ttyUSB[0-9]*", SUBSYSTEM=="tty", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="814a", SYMLINK="ttyS7000"
2. Open JS8Call
3. Go to Radio Settings and set Serial Port to /dev/ttyS7000
4. Test Cat (works)
5. Go to Rig Options and set Serial Port to /dev/ttyS7000
6. Test PTT (JS8Call shuts down with SegFault)

Expected behavior
Should accept and trigger PTT without crashing.

Desktop (please complete the following information):

• OS: Ubuntu 24.04
• Version 2.6.0 master
• Radio Icom IC-7000
• Direct to radio

Not sure why it fails yet on the PTT, but works fine on the CAT control. BTW, this was working fine when both were set to /dev/ttyUSB0