Need init script to run ldconfig on boot
ldconfig is not run in the Buildroot build because the host ldconfig is used (the cross toolchain does not have the proper layout nor a host-ldconfig for Buildroot to use instead) but doesn't work right. So ldconfig needs to run at boot time. It definitely should be run on first boot. It's not clear if it should be made to run on every boot, but probably not. Any installed apps can run it manually on installation.