Comment 9 for bug 307462

I spoke too fast. removing --enable-pthread disables the build of ruby-tk and causes a build failure later in the process:
dh_movefiles -plibtcltk-ruby1.8 \
     usr/lib/ruby/1.8/x86_64-linux/tcltklib.so \
     usr/lib/ruby/1.8/x86_64-linux/tkutil.so
dh_movefiles: debian/tmp/usr/lib/ruby/1.8/x86_64-linux/tcltklib.so not found (supposed to put it in libtcltk-ruby1.8)
dh_movefiles: debian/tmp/usr/lib/ruby/1.8/x86_64-linux/tkutil.so not found (supposed to put it in libtcltk-ruby1.8)
tar: /home/lucas/dev/pkg-ruby/ruby1.8/build-area/ruby1.8-1.8.7.72/debian/movelist: Cannot stat: No such file or directory
tar: Error is not recoverable: exiting now
tar: This does not look like a tar archive
tar: Error exit delayed from previous errors

Doesn't sound like a regression we can live with.