[Pkg-shadow-devel] feature request: add option (--prefix $PREFIX)

[Tjernlund]

--prefix is similar to --root but without the actual chroot.
--prefix is useful when cross compiling and you have your corss
root FS under a subdir such as /usr/powerpc-tm-linux-gnu then
groupadd --prefix /usr/powerpc-tm-linux-gnu would prefix all
/etc/x accesses with /usr/powerpc-tm-linux-gnu/etc/x

Also, any PAM processing should be skipped if --system is specified too