install_dir: Allow one to specify an alternate root dir

This is useful if you install a package to /opt and libs are in /opt/lib:
    $(call install_lib, foo, 0, 0, 0644, libfoo, /opt)

Signed-off-by: Jon Ringle <jringle@gridpoint.com>
Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
systemd: PTXCONF_SYSTEMD_COREDUMP

Allow coredumpctl to be built and installed to debug crashing systemd
services

Signed-off-by: Jon Ringle <jringle@gridpoint.com>
Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>