Цитата
avr-g++.exe -mmcu=atmega1280 -Wall -ffunction-sections -fdata-sections -fstack-usage -DF_CPU=8000000UL -g -c Src\tst.cpp -o Obj\Debug\Src\tst.o
cc1plus.exe: error: unrecognized command line option "-fstack-usage"
Не понимает такой опции

Может, староват компилер?
Цитата
C:\WinAVR\bin>avr-g++ -v
Using built-in specs.
Target: avr
Configured with: ../gcc-4.2.2/configure --enable-win32-registry=WinAVR-20071221
--with-gmp=/usr/local --with-mpfr=/usr/local --prefix=/c/WinAVR --target=avr --e
nable-languages=c,c++,objc,ada --with-dwarf2 --disable-nls --enable-doc --disabl
e-shared --disable-libada
Thread model: single
gcc version 4.2.2 (WinAVR 20071221)