multimedia/mpv: Fix build on arm64

/usr/bin/ld: /wrkdirs/usr/ports/multimedia/mpv/work/mpv-0.27.0/build/mpv: local symbol `__progname' in /usr/lib/crt1.o is referenced by DSO
/usr/bin/ld: final link failed: Bad value
cc: error: linker command failed with exit code 1 (use -v to see invocation)

Reported by: pkg-fallout