I have been getting the error, avr-g++: error: missing filename after '-o'. And it wasn't happening till about a month ago.
The error is caused by using Arduino AVR Boards 1.6.10 with Arduino IDE 1.6.6, they are incompatible. The solution is to either:
- Upgrade to Arduino IDE 1.6.7 or 1.6.8
- Install Arduino AVR Boards 1.6.9 using Boards Manager(Tools > Board > Boards Manager... > Arduino AVR Boards(click on it) > Select version > 1.6.9 > Install) - I've had problems reinstalling the previous Arduino AVR Boards version with Boards Manager so you may have to reinstall the Arduino IDE if you can't compile after going back to Arduino AVR Boards 1.6.9.