Maybe it's my fault, but I can't disable mplayer-runtime-cpudetection.
I think it is caused by MPLAYER_ENABLE_RUNTIME_CPUDETECTION still being
set in pkgsrc/mk/defaults/mk.conf.  At least make says it's set: 

Deprecated variable MPLAYER_ENABLE_RUNTIME_CPU_DETECTION used, use PKG_DEFAULT_OPTIONS+=mplayer-runtime-cpudetection instead.
Deprecated variable USE_ESOUND used, use PKG_DEFAULT_OPTIONS+=esound instead.
Deprecated variable USE_GIF used, use PKG_DEFAULT_OPTIONS+=gif instead.

whereas I removed it from my /etc/mk.conf.  

I have added PKG_DEFAULT_OPTIONS+=-arts -nas -mplayer-runtime-cpudetection
and the first two do have effect.  

GH

-- 
:wq