su failed to chdir with NFS mounted home dir

Hi,

I've encountered a problem with su on NFS mounted home dir. In revision
1.68 of su.c, the code was rearranged to chdir before new uid was set,
this chdir would fail if local root doesn't have permission to enter
the target user's home dir. This is exactly the case when you have a NFS
mounted home dir with 0750 permission while root is mapped to nobody on NFS.

Is there an owner for su.c? I'd like to modify it to delay this chdir to
after the new uid is set.

Thanks
-lq