updating x11/xbindkeys for newer Tcl/Tk

[Will Parsons]

When I went to build xbindkeys with Tcl support, I noticed it was
trying to install Tcl8.4, which is quite old.  Since I already have
Tcl 8.5 and Tcl 8.6 installed, installing Tcl8.4 seemed to be a waste.

I edited the Makefile to replace references to 8.4 with 8.5, and it
seems to build correctly with the later Tcl, but it would seem be good
to have the official port updated.  Seeing how the maintainer is
ports at FreeBSD.org (which I gather means it has no maintainer), is
submitting a PR likely to get this fixed, or does it need an official
maintainer first?

-- 
Will