Update audio/soundkonverter to use new options macros and to always build
The plugins are disabled at run-time if the required programs are not available,
always including them:
a) does not result in a broken port
b) provides greater flexability to the user (if the ports are installed later)
c) increases the build time, although it is a small port in any case.
The above two changes reduces the Makefile line count by 160.
Approved by: eadler,bdrewery (mentors, implicit)