When trying to build readline-5.2 on OS X 10.5 Leopard it fails with the following error:
Thread model: posix gcc version 4.0.1 (Apple Inc. build 5465) i686-apple-darwin9-gcc-4.0.1: -compatibility_version only allowed with -dynamic lib make: *** [libreadline.5.2.dylib] Error 1 make: [shared] Error 2 (ignored)
readline hasn't been updated to look for Darwin 9 when configuring. It is a simple 2 character patch, adding 9 to darwin in ./support/shobj-conf.
There is a tarball here to save (us) repatching this whenever we need it.