- Add Nvidia workaround as option

Some users of Nvidia cards reports very high cpu usage by ecore_x_vsync,
in this case devel/efl should be rebuild with NVIDIA option enabled.

Submitted by:	6yearold <at> gmail <dot> com (via email)


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@374188 35697150-7ecd-e111-bb59-0022644237b5