Testing tcllib-1.12 with Tcl 8.4.19, I see:

[*   ]  [8.4.19]  yaml                  Error in huddle.tcl: bad subcommand "with": must be append, create, ...

The [dict with] command is not part of Tcl 8.4, and
the [package require dict] is apparently getting a
version of the dict package not recent enough to
have the required subcommand.  Adding a version
requirement should help guard against this.

Also, the stanza,

if {$::tcl_version < 8.5} {
    package require dict
}

is buggy.  Use [package vcompare]
instead of trying to treat version numbers
as if they were real decimal numbers.

thank you.
I modified about this.