The main sysroot components of unreachable build targets will be removed by the core
code. This currently doesn't trigger a removal in the individual workdirs. This
adds in symlinking between the complete stamps and the component sysroot meaning
we can detect when someting was removed and hence remove it from the sysroot.
This fixes cases where DISTRO_FEATURES like systemd are changed amongst other
things and makes builds more robust against configuration changes.
If a dependency is rebuild, that is caught by checksum comparision code elsewhere
in this function as before.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
