Added -fpermissive flag.
Added -fpermissive flag.

This avoid build errors on old libraries. It may possibly be removed in
the future after a period of transition.

stickbreaker/Arduino,bsmr-arduino/Arduino,stickbreaker/Arduino,nandojve/Arduino,majenkotech/Arduino,PaoloP74/Arduino,stickbreaker/Arduino,Chris--A/Arduino,bsmr-arduino/Arduino,bsmr-arduino/Arduino,bsmr-arduino/Arduino,Chris--A/Arduino,bsmr-arduino/Arduino,me-no-dev/Arduino-1,PaoloP74/Arduino,nandojve/Arduino,majenkotech/Arduino,majenkotech/Arduino,PaoloP74/Arduino,stickbreaker/Arduino,nandojve/Arduino,PaoloP74/Arduino,nandojve/Arduino,stickbreaker/Arduino,Chris--A/Arduino,majenkotech/Arduino,Chris--A/Arduino,PaoloP74/Arduino,me-no-dev/Arduino-1,PaoloP74/Arduino,me-no-dev/Arduino-1,me-no-dev/Arduino-1,majenkotech/Arduino,nandojve/Arduino,stickbreaker/Arduino,Chris--A/Arduino,me-no-dev/Arduino-1,PaoloP74/Arduino,bsmr-arduino/Arduino,Chris--A/Arduino,Chris--A/Arduino,PaoloP74/Arduino,Chris--A/Arduino,stickbreaker/Arduino,nandojve/Arduino,me-no-dev/Arduino-1,majenkotech/Arduino,nandojve/Arduino,bsmr-arduino/Arduino,nandojve/Arduino,majenkotech/Arduino,me-no-dev/Arduino-1,me-no-dev/Arduino-1,bsmr-arduino/Arduino