Took a further look at MySQL and it's ability to build on Mac OS X DP3.
I made a few minor changes to configure: running configure only lists 'sh' in the process list which causes the test for 'ps' to fail in configure.
And to some MySQL source code which defined '__attribute__' macro for GNU compilers older than 2.8 but I think it should have been old than or equal to 2.9 (I'll follow this up later I guess).
Then I got stuck on the pthreads issue. I'd like to get MySQL to run with Darwin's straight pthread implementation. But Darwin's implementation seems to be missing a few functions like pthread_kill amoung others...