Replaced G_CONST_RETURN by const literal

Signed-off-by: Joni Lapilainen <joni.lapilainen@gmail.com>
XINPUT dependency

Signed-off-by: Joni Lapilainen <joni.lapilainen@gmail.com>
Build fixes

Signed-off-by: Joni Lapilainen <joni.lapilainen@gmail.com>
Link GL libraries

Signed-off-by: Joni Lapilainen <joni.lapilainen@gmail.com>