Bugzilla Bug 209521

If one compiles mplayer with USE="-png" and runs it via
"mplayer -vf-add screenshot"
as smplayer does in _default_ configuration, then mplayer will crash.
There should be either a built check

if ! built_with_use media-video/mplayer png; then
 die "Smplayer needs mplayer to be built with png support, to prevent crashes."
fi

Maybe ewarn instead of die is sufficient. If ewarn is used, there should be a
comment, that one can clear the "Folder for storing screenshots" field to
prevent smplayer from adding -vf-add screenshot to the command line it passes
to mplayer.

See also:
http://smplayer.sourceforge.net/forums/viewtopic.php?id=234

Reproducible: Always

Steps to Reproduce:
1. USE="-png" emerge -v1 mplayer smplayer
2. mv ~/.smplayer ~/.smplayer.old
3. smplayer some_video_file

Actual Results:  
Debug: MplayerProcess::parseLine: 'Opening video filter: [screenshot]'
Debug: MplayerProcess::parseLine: ''
Debug: MplayerProcess::parseLine: ''
Debug: MplayerProcess::parseLine: 'MPlayer interrupted by signal 11 in module:
init_video_filters'
Debug: MplayerProcess::parseLine: 'ID_SIGNAL=11'
Debug: MplayerProcess::parseLine: '- MPlayer crashed by bad usage of
CPU/FPU/RAM.'

Forgot to add, this is of course the case for both versions in portage.

Applied in cvs.