[ excerpt (with adaptations) from developer's website with modifications ]
MKVtoolnix will evolve into a set of tools to create, alter and
inspect Matroska files under Linux and other Unices, just what the
OGMtools do for the OGM format.
===> The following configuration options are available for mkvtoolnix-nox11-74.0.0_1:
DVDREAD=off: Support reading DVD chapters via libdvdread
FLAC=on: FLAC lossless audio codec support
MANTRANS=off: Build and install manpage translations
NLS=on: Native Language Support
===> Use 'make config' to modify these settings
multimedia/mkvtoolnix: FLAVORify port for GUI/non-GUI variants
Implements the suggestions from the ports-committers mailing list:
* Use FLAVOR instead of slave port for the non-GUI variant
* Call non-GUI variant "nogui" instead of "nox11"
Differential Revision: https://reviews.freebsd.org/D39036
multimedia/mkvtoolnix-nox11: Add mkvtoolnix without GUI variant
Details: The default mkvtoolnix package comes with a large number of x11
related dependencies. Without UI, the tools still provide very useful
functionality, and are well suited for headless systems. Having a -nox11
instance of the port allows to provide an official GUI-free package.