devel/tclxml: Prepare for libxml2 update

The build passes CC arguments to LD.
Convert to using CC for linking.

Add missing library dependencies that get picked up automatically,
to ensure a consistent build as a port (outside poudriere).

Sort Makefile to canonical portlint/portclippy ordering.

• This patch was submitted privately and I'd like to thank Matthias for guidance and fixing remaining issues *

PR: 262288
Reported by: antoine (via exp-run)
Approved by: portmgr (blanket)