[boost] how to build boost version 1_34_1 with gcc in non-standard location?

Subject: [boost] how to build boost version 1_34_1 with gcc in non-standard location?
From: Oliver Kullmann (O.Kullmann_at_[hidden])
Date: 2009-04-29 16:14:27

Hello,

I'm wrestling here for a long time with the following problem,
and I would be very glad if somebody could help me here (seems
to be straight-forward, but I can't find anything anywhere on
the subject):

I have to build some C++ code which doesn't compile with the
system gcc version 4.3.1. So I have installed gcc version 4.1.2 locally.
Now that C++ code uses Boost version 1_34_1, and doesn't compile
with higher versions. Alright, so I install 1_34_1; very unfortunately,
linking is necessary, and here is the problem: Obviously I have
to build Boost 1_34_1 with the locally build gcc 4.1.2, and now
how can I tell the Boost-build where to find gcc???

What I found is to use

PACKAGEPATH/bjam/bjam 
  --toolset=gcc-4.1.2 
  --toolset-root=PATH_TO_GCC_DIR 
  --prefix=INSTALLATION_DIR 
  --build-dir=BUILD_DIR 
  "-sGCC_ROOT_DIRECTORY=PATH_TO_GCC_DIR"
  install --without-python

However, as I had to found out after some time, this doesn't have
any effect --- Boost just builds with the system compiler, and
ignores all these specifications of PATH_TO_GCC_DIR.

Now what is the right way to do it??

I would be really glad for help.

Oliver