I have template based jails as described in https://www.freebsd.org/doc/handbook/jails-application.html and /usr/local/ is a link to /rw/usr-local
In jail's /etc/make.conf I have WRKDIRPREFIX?=/rw/portbuild
All ports installs in my jails just fine except devel/ruby-gems.
While building this port installs target gem file in /rw/portbuild/usr/ports/devel/ruby-gems/work/stage/rw/usr-local/bin/gem27 while all other files go to the /rw/portbuild/usr/ports/devel/ruby-gems/work/stage/usr/local
So when I try to make install I get the following error:
pkg-static: Unable to access file /rw/portbuild/usr/ports/devel/ruby-gems/work/stage/usr/local/bin/gem27:No such file or directory
If I copy gem27 to required directory install goes fine.
I think this problem has the same source as https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=249083
devel/ruby-gems somehow uses the real path to /usr/local directory instead of symlink when build staging