Log Message:
Fix build under Linux: instead of hardcoding the manpage name as a build
target (man.0), use 'all' which works (at least) under NetBSD and Linux.
(The problem is that the manpage suffix changes across systems.)

While here, remove a directory emptied during deinstallation.
Bump PKGREVISION to 2 due to this.

This change together with recent rillig@'s fixes close PR pkg/29493.