I would agree with Steve Baker (as discussed elsewhere - sorry, can't find it right now) that 'configure;make' is the standard way of builing on unix environments. I nearly decided against using bullet when I read that it was not using this approach (I just hate installing additional software).
Below a quick Makefile, which can be used in the bullet root directory, and would allow users to use 'configure; make' by first building jam.
It's just a suggestions - if you use it, configure should be somewhat improved to remove the jam message, etc.
Cheers,
Joerg
PS: Just for the record: I am not saying that autoconf is the best way of doing this

PPS: The \t have to be replaced with tabs of course
Makefile:
=========
.PHONY: jam bullet
all: jam bullet
jam:
\t$(MAKE) -C jam-2.5
bullet:
\tjam-2.5/bin*/jam