Finally I managed to build the last avr-libc using cygwin, WinAVR_20040720 and the manual from avr-libc documentation. The only thing which is missing are the folders "ldscripts" inside include and lib.
What did I wrong? Ho can I make this files and folders?
I think my problem are errors like this during final "make install":
ibc.a': No such file
ibm.a': No such file
Curious, because the files are there and not missing.