the ports/news/tin upstream tarball contains a number of scripts
ins "./tools/" directory. some of them get installed without
checking. in particular, even when defining "WITHOUT_TIN_METAMAIL",
a script called "url_handler.sh" is installed, overwriting one from
ports/textproc/urlview. furthermore, the tin version is much inferior,
as commands to handle specific URL schemes ("netscape" for http in a
ncurses-application?!) are hardwired. some perl scripts are installed
without adding perl to RUN_DEPENDS. all scripts have shebang lines from
the linux world: they contain "/usr/bin/" as the command prefix.

the net result of all this:  installed commands cease to work, the tin
versions don't run on freebsd without tweaking.

every time tin gets updated, i have to fix "url_handler.sh"!

Fix: 

as there are RUN_DEPENDS lines for, eg. "metamail", which satisfy
tin requirements, tin must not install its tools version of, eg.
"url_handler.sh". instead, install those tools into local/libexec/tin/
or local/share/tin/, but make sure the shebang paths are correct.  i,
for one, have never used or needed any of the tools.

also, do not install tools explicitly not wanted by the user specifying
"WITHOUT_*" options.
How-To-Repeat: 
after installing tin, try other applications using "url_handler.sh", or
try any other tin-tools.