As you can tell, I didn't get any replies to this, posted some time ago. I did manage to get PHP compiled, though as a newbie myself I'm not entirely sure what fixed it. I tried a lot of things. Here's my best guess, see if it works for you: After you do "./configure", type "make clean" before you do "make." If you've been messing around with configuration parameters a lot as I had, it may help.
I'm still not entirely certain as to the exact function of "make clean," but I assume it must flush caches and such. Perhaps cleaning out files that did not make properly in a previous attempt? Maybe an experienced user could reply and help clear this up.