makepkg: fix recreation of hardlinks to .gz manpages

makepkg: fix recreation of hardlinks to .gz manpages

4ed12ae tightened up the logic to use only find, but ignored the fact
that since the manpage hard link names were no longer captured. They
were created as separate compressed manpages, rather than as hardlinks.

This also introduces a minor efficiency of deleting all hardlinks at
once and using proper iteration over an array rather than a string.

Note to anyone else touching this code: e2fsprogs and libpcap are useful
for testing this. If that changes in the future, you can use the below
bash to locate others:

  IFS=$'\n' read -rd '' -a a < <(find /usr/share/man -type f \! -links 1)
  pacman -Qqo "${a[@]}" | sort -u

I broke it!

Signed-off-by: Dave Reisner <dreisner@archlinux.org>