Got sidetracked from this a bit and I just now got back to it. I got it to compile using Arduino 1.6.5 and Teensyduino 1.25 (not the beta). There was also an issue with the latest aJson due to this commit:
They conditionalize the location of the pgmspace.h include:
But apparently the Teensy still puts it in avr/pgmspace.h even though it’s not really an AVR. I changed
#if defined(__AVR__) || defined(TEENSYDUINO)
And it works now. I’ve submitted a pull request for aJson: https://github.com/interactive-matter/aJson/pull/79
UPDATE: I’ve done a bit more testing and determined the problem seems to be Arduino 1.6.6 or later. I got it to successfully compile using Arduino 1.6.5-r5 and Teensyduino 1.27. I’ve updated the wiki compilation instructions to include the caveats I’ve discovered.
I’m not sure where to start debugging the compilation issues with 1.6.6 and later… I will leave that to the professionals. If you think it would be helpful I can ask for help on the PJRC forums.