Comment # 47 on bug 1211796 from Jan Engelhardt

>scripts/depmod.sh effectively calls 'depmod -b $INSTALL_MOD_PATH'
>but `make modules_instdall` won't install under usr/ prefix.

The following works for me on the pristine kmod-30:

  make modules_install INSTALL_MOD_PATH=/Someroot/usr

The files generated by depmod do not carry any prefixes that I can see, so it
does not matter that it called

  depmod -b /Someroot/usr

instead of

  depmod -b /Someroot --somenewoption=/usr

the resulting rpm should be the same to a rpm consumer, i.e. next system boot
once that rpm is installed.