audio/taglib: Fix packaging if TEST option is enabled

• Add STATIC option to fix packaging if the TEST option is enabled. Taglib only allows for static libraries to be built when testing is enabled. [1]
• devel/cppunit needs to be present at build time for the tests to be built.
• Enable symbol visibility.
• Boost support was removed upstream, so we no longer need to disable the check for it.

PR: 246203 [1]
Submitted by: <daniel.engberg.lists@pyret.net> [1]
Reported by: <sdalu@sdalu.com> [1]