I still don't understand why libncurses is linked against libtinfo but
libreadline is not.  Again, what is your OS?

Example Ubuntu (a modern system):

$ ldd /lib/x86_64-linux-gnu/libncurses.so.5
        linux-vdso.so.1 =>  (0x00007fff5bfed000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fcb8b43a000)
        libtinfo.so.5 => /lib/x86_64-linux-gnu/libtinfo.so.5 (0x00007fcb8b211000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fcb8ae4a000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fcb8b87d000)

$ ldd /lib/x86_64-linux-gnu/libreadline.so.6
        linux-vdso.so.1 =>  (0x00007fff8c5fe000)
        libtinfo.so.5 => /lib/x86_64-linux-gnu/libtinfo.so.5 (0x00007f43055a0000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f43051da000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f4305a2b000)