Allow building of mpv and mplayer packages without being installed

[survient]

I'd like to package xsecurelock for Fedora with the mpv and mplayer packages included however the current build process for xsecurelock require that paths to the mpv and mplayer binaries be provided for each respective packages. Fedora does not include mplayer or mpv in its repositories due to licensing issues and I'm not able to satisfy these build dependencies at present in trying to include these packages.

If the binaries are not a hard requirement to build the corresponding xsecurelock packages then I'd request that the configure process be modified to allow an override or some change in logic that doesn't require the binaries to be present to include the packages. Users installing the software would be able to get base functionality out of the main rpm package and additional functionality if they install the needed mpv and mplayer dependencies.