I have no idea on which platforms these tests were made. On Linux I can reproduce this error, so perhaps someone wants to give it a try. I still have the complete log on http://lospalmos.net/boost-logs/boost-gcc-4.0.2.log fo those who need complete build logs for error detection. Since boost uses a build system of its own I do not have the time to debug these builds scripts.
Let me be very clear about this: there are absolutely no hardcoded dependencies to ICU, looking though your build script I see that you have invoked bjam twice: the first invocation succeeds, the second fails because someone has added HAVE_ICU to the build environment, so the Jamfile just trusts that ICU is really there and attemps to build in support for it. Actually even if ICU is present this will fail: you have to decide to build either with or without ICU support in regex, you can't sit the two options side by side at present and build both (because the libs and object files all have the same name). That's something I should fix, but in the mean time I believe your problem is caused by your build script. HTH, John.