I am new to most of this command line stuff, but I had this problem trying to configure MySQL.
If you haven't already solved this problem, you may try using "./configure CC=gcc-3.x" to specify that configure use the gcc 3.x compiler which is still on Mac OS X 10.4.x
You can also use "gcc_select" to specify a system-wide default compiler. You can see more by typing "man gcc_select" at your command line prompt to see the man page.