[Boost-build] Trouble building Boost 1.47 64-bit libraries on Linux with gcc. Error is "sorry, unimplemented: 64-bit mode not compiled in"

Subject: [Boost-build] Trouble building Boost 1.47 64-bit libraries on Linux with gcc. Error is "sorry, unimplemented: 64-bit mode not compiled in"
From: Tim Musson (Tim.Musson_at_[hidden])
Date: 2011-12-12 13:31:51

I think I must have a basic misunderstanding or incorrect configuration, 
but I am not able to build 64-bit Boost libraries. The example below is 
for the Thread library, but the Chrono lib had the same error (but on 
error_code.cpp). For history, I have compiled the 32-bit versions fine.

If it matters, the host processor is 32-bit OS (64-bit Intel proc?) and 
I want to cross-compile for 64-bit OS and 64-bit Intel / Xeon proc.
[user_at_machine boost_1_47_0]$ cat /etc/issue
Scientific Linux SL release 4.9 (Beryllium)
Kernel \r on an \m

[user_at_machine boost_1_47_0]$ uname -a
Linux machine 2.6.9-89.0.20.EL #1 Tue Feb 2 19:06:41 CST 2010 i686 i686 
i386 GNU/Linux

Thanks,
Tim

p.s. I searched the boost.build archives for "64-bit mode not compiled 
in" and found relevant.

Example:
[user_at_machine boost_1_47_0]$ ./bjam --with-thread address-model=64

Building the Boost C++ Libraries.

Component configuration:

     - chrono                   : not building
     - date_time                : not building
     - exception                : not building
     - filesystem               : not building
     - graph                    : not building
     - graph_parallel           : not building
     - iostreams                : not building
     - math                     : not building
     - mpi                      : not building
     - program_options          : not building
     - python                   : not building
     - random                   : not building
     - regex                    : not building
     - serialization            : not building
     - signals                  : not building
     - system                   : not building
     - test                     : not building
     - thread                   : building
     - wave                     : not building

...patience...
...found 523 targets...
...updating 16 targets...
common.mkdir bin.v2/libs/thread/build/gcc-3.4.6/release/address-model-64
common.mkdir 
bin.v2/libs/thread/build/gcc-3.4.6/release/address-model-64/threading-multi
common.mkdir 
bin.v2/libs/thread/build/gcc-3.4.6/release/address-model-64/threading-multi/pthread
gcc.compile.c++ 
bin.v2/libs/thread/build/gcc-3.4.6/release/address-model-64/threading-multi/pthread/thread.o
libs/thread/src/pthread/thread.cpp:1: sorry, unimplemented: 64-bit mode 
not compiled in

     "g++"  -ftemplate-depth-128 -O3 -finline-functions -Wno-inline 
-Wall -pthread -fPIC -m64 -Wno-long-long -DBOOST_ALL_NO_LIB=1 
-DBOOST_THREAD_BUILD_DLL=1 -DBOOST_THREAD_POSIX -DNDEBUG  -I"." -c -o 
"bin.v2/libs/thread/build/gcc-3.4.6/release/address-model-64/threading-multi/pthread/thread.o" 
"libs/thread/src/pthread/thread.cpp"