Now that I very carefully read the log you posted I see that it had problems with patching:
# Found patch file "/usr/home/jim/boost_rt/develop/patch_boost". Executing it.
/usr/home/jim/boost_rt/develop/patch_boost: line 4: pushd: ./tools_bb/src/tools: No such file or directory
mv: rename gcc.jam to gcc.jam.prev: No such file or directory
cat: gcc.jam.prev: No such file or directory
patch_boost fixup: ./tools_bb/src/tools
/usr/home/jim/boost_rt/develop/patch_boost: line 9: popd: directory stack empty
~/boost_rt/develop/boost_root/tools/build/src/tools ~/boost_rt/develop
patch_boost fixup: ./boost_root/tools/build/src/tools
~/boost_rt/develop
FYI.. "tools_bb" is one of the paths I changed in the new scripts. I normalized all the fetched dirs to start with "boost_". So that dir is now "boost_bb".