First of all, thanks for your answers!

I copied all archive contents beside /include/g++-3/ (this directory
has been already exist in my GG:). I also copied OS3.9 includes to
GG:m68k-amigaos/os-include. Then in my makefile I set CC variable to
GG:lib/gcc-lib/m68k-amigaos/2.95.3/gcc
When I'm trying to make a project, I'm getting this message:
Assembler messages:
Error: invalid switch -mc68010
make: *** [o/clipboard.o] Error 1

What should I do now?