add option --T_dont_fork to tracee (lte-softmodem, oaisim)
The T has 2 processes: the tracee and the local tracer if the tracee dies (segfault or whatever) the tracee may still be running. So there is a third process that monitors those two others and kill everything when one dies. The problem is that this third process has to be the parent of the two others. That makes debugging the tracee with gdb impossible. This new option disables the third monitor process.