Comment 3 for bug 1628879

And another time:

```
* thread #1: tid = 0x1e6956, 0x00007fff98b76f8a libsystem_kernel.dylib`__read_nocancel + 10, stop reason = signal SIGSTOP
  * frame #0: 0x00007fff98b76f8a libsystem_kernel.dylib`__read_nocancel + 10
    frame #1: 0x00007fff9e96c155 libsystem_c.dylib`_sread + 16
    frame #2: 0x00007fff9e96b769 libsystem_c.dylib`__srefill1 + 24
    frame #3: 0x00007fff9e964a60 libsystem_c.dylib`fgets + 106
    frame #4: 0x000000010c5e8beb libngspice.0.dylib`promptreturn + 109
    frame #5: 0x000000010c5e8d5b libngspice.0.dylib`out_send + 237
    frame #6: 0x000000010c5e8e04 libngspice.0.dylib`out_vprintf + 38
    frame #7: 0x000000010c5e8eb4 libngspice.0.dylib`out_printf + 148
    frame #8: 0x000000010c5c29a2 libngspice.0.dylib`inp_dodeck + 1063
    frame #9: 0x000000010c5b6066 libngspice.0.dylib`doblock + 911
    frame #10: 0x000000010c5b59b1 libngspice.0.dylib`cp_evloop + 1972
    frame #11: 0x000000010c5a925b libngspice.0.dylib`runc + 422
    frame #12: 0x000000010c5a908b libngspice.0.dylib`ngSpice_Command + 63
    frame #13: 0x000000010be47f3e _eeschema.kiface`NGSPICE::Command(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) + 238
    frame #14: 0x000000010be44510 _eeschema.kiface`NGSPICE::Init() + 176
    frame #15: 0x000000010be217c8 _eeschema.kiface`SIM_PLOT_FRAME::SIM_PLOT_FRAME(KIWAY*, wxWindow*) + 1704
    frame #16: 0x000000010be24fc5 _eeschema.kiface`SIM_PLOT_FRAME::SIM_PLOT_FRAME(KIWAY*, wxWindow*) + 37
    frame #17: 0x000000010bc7cb8a _eeschema.kiface`SCH::IFACE::CreateWindow(wxWindow*, int, KIWAY*, int) + 378
    frame #18: 0x00000001000a497d kicad`KIWAY::Player(FRAME_T, bool, KIWAY_PLAYER*) + 541
    frame #19: 0x000000010be19303 _eeschema.kiface`SCH_EDIT_FRAME::OnSimulate(wxCommandEvent&) + 67
```