New build system

OK, I've fixed a bug with dependencies, where it wouldn't re-build a C file if a header changed. I've also added some "configure" support. So modules like rlm_pam, python, perl, etc. only get built if their prerequisites are found. One benefit is that "make -j 8" now works. On my quad-core system I get this: $ time make -j 8 clean all ... real 0m4.357s user 0m24.702s sys 0m3.580s A complete build in less than 5 seconds. Very nice! Alan DeKok.