Sergey, I'm glad it worked for you.
Actually, what you did is not what I meant for you to do. Instead of downloading and running entware_install.sh, I suggested you download and run opkg. I should have been clearer, sorry.
I'm a bit puzzled as to why this has worked. All you did was remove a symbolic link /opt/lib/libc.so.6, which would have been pointing to
libc-2.23.so, and now will still be pointing to
libc-2.23.so. The first time running the installer, it complained that the symlink already existed ("File exists"), but then it should have carried on, with the existing symlinks in place. In fact, before trying to create the symlinks, the installer has already replaced both the opkg binary and the library files it uses, which were the suspect files, and so the rest of the installer should have worked - the output shows that it didn't, of course. So this is puzzling. My best guess is that the symlink you removed was pointing to a different library altogether, and in removing the symlink, you allowed it to be recreated by the installer, pointing to the correct library.
Oh well, all's well that ends well.
Cheers
Jeremy