http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57631
--- Comment #10 from Georg-Johann Lay <gjl at gcc dot gnu.org> --- I can have a look at it, but it might take a month or so until I get back to this issue. If I understand correctly, bottom line of what you need is that avr-gcc does not warn for ISR names that are not of the form __vector* Maybe a new command line option -W[no-]isr-name or similar is more general? The default of the option would be 'on' per default.
