i get:
./configure[17927]: /ruby: not found
./configure[17927]: ${exec_prefix}/lib: not found
./configure[17937]: /ruby/site_ruby: not found
./configure[17937]: ${exec_prefix}/lib: not found
but configure finishes. later (after make, make install) when trying to install rubygems i get
./lib/rubygems.rb:10:in `require': no such file to load -- thread (LoadError)
=begin
It seemed that 1.8.6p383 need to back port r15777 and r15779.
At least, I was able to install rubygems by using attached patch.
This issue did not occur on ruby_1_8.