[glob] + [file tail] gives wrong result

Binary package hint: tcl8.5

This bug is reported upstream as: https://sourceforge.net/tracker/index.php?func=detail&aid=2710920&group_id=10894&atid=110894

In a specific scenario involving [glob] with a trailing slash, the
resulting files are treated improperly by [file tail]. An attached script,
which can be run by
$ tclsh fff.tcl

Expected output:
/bin/ /bin
Actual output:
/bin/ {}

("bin" can be another directory name such as "mnt" or "etc"; it depends on the order of directories returned by [glob]. The important thing is that [file tail] returns an empty string when it should return a non-empty one)

In my application, the only observed consequence of this bug is to display an empty string onscreen where a directory name should be shown, but if the result of [file tail] is used to decide on a file to use for input or output, this bug could change the file actually being opened.