To run, first read through setup.sh, and make sure it won't do anything 
you don't want it to do on your system.  Then set the values of 
src_gcc, src_src, and dst_root, and run setup.sh.    The script will 
rsync the checked-out gcc and src sources into a new directory, apply 
the patches, and run autoreconf on all the appropriate directories.

I've built directory on i386-unknown-linux-gnu native, targetted to 
powerpc-unknown-linux-gnu, and natively on i686-pc-cygwin (I got some 
errors building winsup on cygwin, but they were the same errors I got 
from the unmodified sources).  I've *not* run extensive tests on the 
resulting builds --- I'm willing to do that, but it seemed a bit early 
at this stage.

I did not attempt to make the patches compatible with both 
autoconf-2.13 and autoconf-2.5x --- I suspect that would be a 
significant challenge, and converting to automake-1.7 and autoconf-2.5x 
was difficult enough.