The files in the subdirectory lib should be installed in /usr/local/lib.
The gcc binary in the bin subdirectory can go anywhere you like.

The file gcc-3b1.diffs gives the diffs I applied to the stock versions
of the 3b1 configuration files in the config subdirectory.

The only other file I modified was the Makefile;  you're own your own there.
My changes were so that I could cross compile, and really were very simple
(CC= and CFLAGS= lines, I believe).

If you prefer to use the native assembler rather than gas, then
remove lib/gcc-as and move native/gcc-cc1 to lib/gcc-cc1.  Also use
native/gcc rather than bin/gcc.

One final note -- shld.shar.Z.  This is a front end to the ld program,
and provides the same functionality as "shcc" for "gcc -shlib".  It's
strictly optional, but makes linking with the shared library easier.
If you want it, unpack the shar file and follow the instructions.