tabs.1 is installed as a dangling symlink

[Sven Joachim]

Not sure when this broke, but in the current patchlevel (20190713),
"make install" installs tabs.1 as a symlink to itself:

,----
| $ ./configure --prefix=/tmp/ncurses && make install
| [...]
| $ LC_ALL=C ls -l /tmp/ncurses/share/man/man1/tabs*
| lrwxrwxrwx 1 sven sven 6 Jul 15 12:36 /tmp/ncurses/share/man/man1/tabs.1 -> 
tabs.1
`----

In the "make install" output I see the following messages:

,----
| installing /tmp/ncurses/share/man/man1/tabs.1 tabs.1.gz
| .. installing alias tabs.1
`----

I don't know what the intention was, but installing tabs.1 as an alias
(= symlink) to itself cannot be right.

Cheers,
       Sven