Way back in July, someone mentioned a problem with getting PHP/MySQL to compile into Apache. I may have run into the same problem.
While ./configure'ing Apache for the second time, ld fails when compiling dummy.c because of unresolved symbols, 'compress' and 'uncompress'.
This is apparently fixed by linking in the zlib -- that is, adding -lz to the compile options. I can't find a place to do that with apaci, sooo I edited src/configure, found the platform-dependent stuff, and modified the line:
LIBS = "$LIBS"
to be
LIBS = "-lz $LIBS"
and it seems to be working quite a bit better. Your mileage may, of course, vary.
PS: problem discovered when I upgraded php3, apache, mysql, and NetBSD all in one sitting. So I'm not sure which change broke this...