packaging a GCC binary distribution so it can be installed at arbitrary locations?

[Gary Funck]

Given a binary distibution of GCC, for example, built to install under
/usr/local, is it possible to configure and build the compiler in such a
way that a binary packaging method such as RPM can allow a user to specify
an alternate installation point (perhaps /opt, or even the user's home
directory) and have it all work?

My impression is that too many hard coded paths are wired into gcc.c when
it is built to make this ability to migrate the binary possible.  There are
workarounds for the user such as setting various environment variables and
using the -B switch, but I'm looking for a method that directly allows installation
of the binary to a new place than where it was initially configured.  Anyone found
a way to do this?  (Separately, GCC 3.4 is now built using dynamic libraries
for libgcc and libunwind, and these cause some different but unique problems
invoking gcc [assuming the user would prefer not to adjust their library path
or doesn't have access to /etc/ld.so.conf. I think things could be made
simpler by specifying various -rpath settings when the executable is linked,
but these -rpath settings may have to fixed up when installing the binary
to a place other than it was built, unless the entries can be made relative
to the executable.])