Just managed to build a  AVR toolchain with the latest 4.5.0 gcc.

Tested for Atmel 644P and Atmel 328P 🙂

Linux AVR Toolchain:

• gcc 4.5.0
  • gmp 5.0.1
  • mpfr 2.4.2
    • latest cumulative patchset see
• binutils 2.20.1
  • avr patchset: size, new devices, xmega and new sections
• AVR Libc 1.6.8

Toolchain download size 71M.

Have fun!