This makefile script downloads, patches, builds and installs all prerequisites required
by the GNU toolchain for AVR, as well as the toolchain itself.

To test if all builds correctly:
$ make -j4

To build and install:
$ make clean
# make -j4 LIBPREFIX= GCCPREFIX=/opt/avr-gcc-4.5.1

In case of problems, see instructions in:
http://www.nongnu.org/avr-libc/user-manual/install_tools.html

Patches come from:
http://distribute.atmel.no/tools/opensource/avr-gcc/