This solution works only on arch linux and derivate. Corrected commands are:
32bit pacman -U /var/cache/pacman/pkg/gcc-avr-4.6.0-3-i686.pkg.tar.xz
64bit pacman -U /var/cache/pacman/pkg/gcc-avr-4.6.0-3-x86_64.pkg.tar.xz
you can also blacklist gcc-avr in /etc/pacman.conf