cross-avr/gcc NEEDS multilib for AVR, or you will get crtXXX.o not found when linking
cross-arm-none-eabi/gcc requires EXTRA_ECONF="--disable-libstdcxx-time" or it will fail to compile
cross-arm-none-eabi/gcc requires EXTRA_ECONF="--disable-multilib --with-arch=armv6s-m: or it will give you a hardfloat toolchain that will brick your SAMDs
cross-avr/binutils requires the patch in #2 or it will cause you grief if not using recent binutils-config
cross-avr/gcc NEEDS multilib for AVR, or you will get crtXXX.o not found when linking cross-arm-none-eabi/gcc requires EXTRA_ECONF="--disable-libstdcxx-time" or it will fail to compile cross-arm-none-eabi/gcc requires EXTRA_ECONF="--disable-multilib --with-arch=armv6s-m: or it will give you a hardfloat toolchain that will brick your SAMDs cross-avr/binutils requires the patch in #2 or it will cause you grief if not using recent binutils-config