when the board due is selected there is a problem with an undefined debug mode cc
this appears to be cause by one line in
that end with "-gcc"
Simply editing the file and removing that option allowed compile and upload of blink to the due with no further problem. (It appears to be something that was required by the old gcc 4.x however arduino18 uses new gcc 8.x)
Created attachment 204443 [details]
patch to remove the -gcc option