New ThreadDebug Commit - g++ not found in %PATH%

Hello All (Martino),

Trying your [latest commit](https://github.com/arduino/ArduinoCore-mbed/commit/197b1b8a194ce9435cf7faed53f447cfa0e6458d) with the ThreadDebug lib - getting this:


Compilation error: Error: 2 UNKNOWN: exec: "g++": executable file not find in %PATH%.

Probably an easy one to fix - just wanted to report it - I'll see if I can do a workaround since I really want to see this run.

Compiling...
{
"sketchUri": "file:///c%3A/tmp/demo-web-server/demo-web-server.ino",
"fqbn": "arduinobeta:mbed:envie_m7_thread_debug", <=== is that a possible reason?
"optimizeForDebug": true
}

Also seeing:
Error during Debug: Cannot get command line for tool: cannot get programmer tool: undefined 'debug.tool' property

It does appear to be running from the command line:
C:\tmp\demo-web-server\build\arduinobeta.mbed.envie_m7>C:\Users\John\AppData\Local\Arduino15\packages\arduino\tools\arm-none-eabi-gcc\7-2017q4\bin\arm-none-eabi-gdb -ex "set pagination off" --baud 230400 -ex "set target-charset ASCII" -ex "set print pretty on" -ex "set remotelogfile mri.log" -ex "target remote COM4" demo-web-server.ino.elf
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Reading symbols from demo-web-server.ino.elf...done.
Remote debugging using COM4
setup () at c:\tmp\demo-web-server/demo-web-server.ino:28
28 void setup() {
(gdb) finish
Run till exit from #0 setup () at c:\tmp\demo-web-server/demo-web-server.ino:28
Note: automatically using hardware breakpoints for read-only addresses.
[New Thread 604075640]
[New Thread 604081468]
main () at C:\Users\john\AppData\Local\Arduino15\packages\arduinobeta\hardware\mbed\1.2.2\cores\arduino\main.cpp:47
47 loop();

Also - in ThreadDebug 'mode' - two identical COM ports are listed:


Thanks!
John W.

Start with the referenced ThreadDebug commit and the Windows compilation and debug-launch path for fqbn arduinobeta:mbed:envie_m7_thread_debug. Reproduce the missing g++ error, undefined debug.tool error, and duplicate COM-port entries; done means each reported ThreadDebug symptom has a verified resolution or a documented cause.

Written by the indexing model from the issue text.