multimedia/mlt7: add option to allow build with audio/libebur128 instead audio/ebur128 if PLUS module enabled

[vvd]

Summary

Module PLUS require audio/ebur128 by default.
Port audio/ebur128 require lang/rust for build.
There is very small audio/libebur128 on C without any additional dependencies.

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=272843

[arrowd]

PLUS implies EBUR* and EBUR* implies PLUS? This looks wrong.

[vvd]

In D41473#944573, @arrowd wrote:

PLUS implies EBUR* and EBUR* implies PLUS? This looks wrong.

All correct:

• EBUR used for PLUS only, so if turn on EBUR, then automatic turn on PLUS;
• PLUS require EBUR.

This is the "logic".

[jhale]

I committed R11:3b2ff2ef194c and R11:f0f843322841 (plus a quick typo fix R11:5f6b3eda2234) to address this issue. You can now set:

DEFAULT_VERSIONS+= ebur128=legacy

in make.conf to use the C implementation tree-wide.

[vvd]

Thanks!