Ruby 1.8.6, zlib and x86_64 problems

Im trying to install ruby 1.8.6 on an x86_64 centos 4.2 system. i’ve
done this install several times on an i386 system with no problems. here
i have ran into this…

first i installed zlib-1.2.3 from source with ./configure make make
install. i then installed ruby from source with ./configure make make
install. no problems yet. then i tried to install rubygems-0.8.11 with
ruby setup.rb and this is where i hit the first wall. after the warning
about library stubs not being needed and telling me that no library
stubs were found it then spit out an error from custom_require saying
about zlib:

" relocation R_X86_64_32 against `a local symbol’ can not be used when
making a shared object; recompile with -fPIC".

so i went back and found a post about installing zlib via yum install
zlib-devel. so i uninstalled the zlib source and installed the devel via
yum. while attempting to recompile ruby i get this:

make[1]: Leaving directory /usr/local/src/ruby-1.8.6/ext/win32ole' compiling zlib make[1]: Entering directory/usr/local/src/ruby-1.8.6/ext/zlib’
make[1]: *** No rule to make target ruby.h', needed byzlib.o’. Stop.
make[1]: Leaving directory `/usr/local/src/ruby-1.8.6/ext/zlib’
make: *** [all] Error 1

any ideas?