pipe-loader: split out "client" version

Build two versions of pipe-loader, with only the client version linking
in x11 client side dependencies.  This will allow the XA state tracker
to use pipe-loader.

Signed-off-by: Rob Clark <robclark@freedesktop.org>
st/xa: use pipe-loader to get screen

This lets multiple gallium drivers use XA.

Signed-off-by: Rob Clark <robclark@freedesktop.org>
st/xa: missing handle type

DRM_API_HANDLE_TYPE_SHARED is zero, so doesn't actually fix anything.
But we shouldn't rely on SHARED handle type being zero.

Signed-off-by: Rob Clark <robclark@freedesktop.org>
pipe-loader: add pipe loader for freedreno/msm

Signed-off-by: Rob Clark <robclark@freedesktop.org>