graphics/glew-wayland: suggest LD_LIBMAP for session-local override

LD_LIBMAP can be limited to Wayland or KMS console e.g.,

$ cat >>~/.zshrc
if | -z $DISPLAY ) && $LD_LIBMAP != *GLEW-wayland*; then

export LD_LIBMAP=libGLEW.so.2=libGLEW-wayland.so.2,$LD_LIBMAP
export SDL_VIDEODRIVER=wayland,kmsdrm,x11

fi