Otherwise, we end up propagating those dependencies into targets that
link against that library, which creates unnecessary link-time
dependencies.
Also included are changes to readd now missing dependencies to tools
that actually need them.
This also improves Commonmark coverage, e.g. it fixes tests
HTML_blocks_ex179_2894..2906 and Lists_ex308_5439..5457.
In other words, we go from 271 out of 652 to 273 out of 652.
